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This work may not be reproduced in whole or in part, by photocopy or other means, without the permission o f the author. 1 ^ 1 National Library of Canada Bibliothèque nationale du Canada Acquisitions and Bibliographic Services Acquisitions et services bibliographiques 395 Wellington Street Ottawa ON K1A0N4 Canada 385, rue Welinglon Ottawa ON K1A0N4 Canada Ycurm m V a im r é M m K » Ourm AMranMeanc* The author has granted a non­ exclusive licence allowing the National Libraiy o f Canada to reproduce, loan, distribute or sell copies of this thesis in microform, paper or electronic formats. L’auteur a accordé une licence non exclusive pam ettant à la Bibliothèque nationale du Canada de reproduire, prêter, distribuer ou vendre des copies de cette thèse sous la forme de microfiche/film, de reproduction sur papier ou sur format électronique. The author retains ownership of the copyright in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author’s permission. L’auteur conserve la propriété du droit d’auteur qui protège cette thèse. Ni la thèse ni des extraits substantiels de celle-ci ne doivent être imprimés ou autrement reproduits sans son autorisation. 0-612-62472-2 Canada APPROVAL Name: Kevin Gordon Driscoll Degree: Master o f Science Thesis Title: SOIL NITROGEN CONTENTS AND CLASSfflCATION OF SELECTED POST-FIRE SITES IN THE SUB-BOREAL SPRUCE ZONE OF CENTRAL BRITISH COLUMBIA Examining C o m m itt^ Chair: Dr. Max Blouw, Dean o f Graduate Studies ipervisor; Dr. Joselito M. Arocena, 'acuity o f Natural Resources and Environmental Studies Dr. IR i^ e s B. Mpsncdtte, F a c in g o fN a tt^ l Resoutces and Environmental Studies iX o ô k jü J k Dr. Roger D. Wheate, Faculty o f Natural Resources and Environmental Studies Dr. Brad C. Hawkes, Fire Research Officer, Canadian Forest Service r: Dr. Paul Sanborn, Research Pedologist, British Columbia Ministry o f Forests Date Approved: in J u .- v ABSTRACT Short and long term planning for sustainable forest management is beset by limited knowledge about the soils and their properties. This thesis was conducted in the McGregor Model Forest to provide relevant information on the types and nitrogen contents of selected soils in the very wet, cool Sub-boreal Spruce biogeoclimatic subzone in the central interior o f British Columbia. Thirteen post-fire sites were selected and grouped as Early Serai (four sites < 1 4 years post-fire), Mid-Seral (five sites 50 - 80 years post-fire) and Late Serai (four sites > 140 years post-fire). Fifteen pedons were sampled and analyzed for physical and chemical properties as well as the contents of total nitrogen, mineralizable nitrogen, available nitrate and ammonium. Five pedons were classified as Eluviated Dystric Brunisols, two as Gleyed Eluviated Dystric Brunisols, five as Orthic Humo-Ferric Podzols, two as Orthic Gray Luvisols, and one as a Rego Humic Gleysol. Incipient podzolization seems to be the dominant pedogenic process in the area along with clay movement (lessivage) and minor hydromorphic processes. With time, it is anticipated that four o f the Eluviated Dystric Brunisols will develop into Porthic Humo-Ferric Podzols and the fifth will become an Orthic Gray Luvisol. The three gleyed pedons were the result o f changes in microtopography. Total N ranged between 0.012 - 0.59% and 0.45 - 2.6% in the mineral and forest floor horizons, respectively, with no significant difference observed between the age classes. Mineralizable N ranged between 11.2 - 146 ppm in the mineral horizons and 308 - 2044 ppm in the forest floor. Available ammonium ranged firom 1.4 - 25.3 ppm (mineral horizons) and 23.2 - 647 ppm (forest floor horizons). Both available ammoniiun and mineralizable N levels were highest in -iii- the forest floor horizons o f the Mid-Seral sites. Available nitrate ranged from 0.005 - 27.6 ppm and 0.005 - 209 ppm in the mineral and forest floor horizons, respectively. With time, available nitrate approaches an equilibrium level as indicated by the decrease in the concentration ranges from the Early Serai to the Late Serai age classes. Where significant differences were noted in the mineralizable and available nitrogen analyses, the Early Serai age classes were generally separated from the older age classes. -IV - TABLE OF CONTENTS Approval ii Abstract iü Table o f Contents v List o f Tables vüi List o f Figures x Acknowledgements xi Chapter One INTRODUCTION LI Rationale 1.2 Research Objectives 1.3 Research Hypotheses 1 I 4 4 Chapter Two STUDY AREA AND CHARACTERISTICS 2.1 Surficial Geology 2.2 Soil Series o f the Study Areas 2.3 Biogeoclimatic Ecosystem Classification 5 5 7 10 Chapter Three REVIEW OF LITERATURE 3.1 Classifying Soils 3.2 Taxonomic Systems o f Classification 3.2.1 Canadian System o f Soil Classification 3.2.2 USDA Soil Taxonomy 3.3 Soils o f the McGregor Model Forest 3.4 Ecological Role of Fire 3.5 Fire Causes and Patterns 3.6 Fire Types and Heat Movement in Forest Floors and Soils 3.7 Fire Patterns within the McGregor Model Forest 3.7.1 The SBS Subzones within the McGregor Model Forest 3.8 Fire and Soil Nutrients 3.8.1 Post-Fire Nutrient Cycling 3.8.2 Post-Fire Nitrogen Levels Summary o f Soil/Fire hiteractions 3.9 -V - 18 18 18 19 20 21 21 24 25 31 32 36 37 45 51 TABLE OF CONTENTS (cont) Chapter Four MATERIALS AND METHODS 4.1 Soils o f the McGregor Model Forest: ARC/INFO Database Preparation 4.2 Site Selection 4.3 Sample Collection and Preparation 4.4 Soil Temperature 4.5 Soil Characterization 4.5.1 Particle Size Analysis 4.5.2 pH 4.5.3 Exchangeable Cations and Cation Exchange Capacity 4.5.4 Extractable Fe and A1 4.6 Soil Classification 4.7 Nitrogen Analyses 4.7.1 Total N and C/N Ratio 4.7.2 Available NO3' and NH»" 4.7.3 Mineralizable N 4.7.4 Projection of Nitrogen Concentrations 4.8 Statistical Analyses Chapter Five Chapter Six 53 53 54 54 55 56 56 56 56 57 58 58 58 59 59 60 60 RESULTS AND DISCUSSION 5.1 ARC/INFO Database 5.2 Soil Classification and Pedon Characteristics 5.2.1 The Eluviated Dystric Brunisols 5.2.2 The Orthic Humo-Ferric Podzols 5.2.3 The Orthic Gray Luvisols 5.2.4 The Gleyed Eluviated Dystric Brunisols and the Rego Humic Gleysol Nitrogen Concentrations and Age Class Analysis 5.3 5.3.1 Total N 5.3.2 Available NO^ and NH»^ 5.3.3 Mineralizable N 5.3.3.1 Mineralizable N and Site Quality 5.3.4 C/N Ratio 5.3.5 Nitrogen and Vegetation Coverage 5.3.6 Projections of Nitrogen Concentrations within the MME 77 85 88 91 97 100 103 106 110 SUMMARY AND CONCLUSIONS 6.1 Forest Management Implications 6.2 Recommendations 113 115 116 -V I- 63 63 64 65 70 72 TABLE OF CONTENTS (cont) Literature Cited Appendix A Appendix B Appendix C Appendix D 118 Soil Associations, Topography and Parent Material in the McGregor Model Forest (attached map) Profile descriptions, diagnostic horizons and/or properties for Pedons 2 ,3 ,4 ,6, 7, 8, 10,1 lu, 1Im, 12,13. 131-145 Selected physical and chemical properties for Pedons 2 ,3 ,4 ,6, 7 , 8,1 0 ,1 lu, 1Im, 12,13. 146-157 Complete data set fiom nitrogen analyses. 158-163 -vu- LIST OF TABLES 2.1 2.2 2.3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 5.12 5.13 Locations of study sites. Soil associations and selected properties determined for each of the study sites. Inventory of vegetation for sites 1-12. Defining taxa for the various categorical levels within the Canadian System of Soil Classification. Soil Series of the McGregor Model Forest. Fires within the McGregor Model Forest between 1951 and 1991 according to biogeoclimatic subzone. Causes o f fires within the McGregor Model Forest between 1951 and 1991. Fires in the SBSvk biogeoclimatic subzone within the McGregor Model Forest. Fires in the SBSmk biogeoclimatic subzone within the McGregor Model Forest. Fires in the SBSwk biogeoclimatic subzone within the McGregor Model Forest. Nutrient changes in streams following a Pacific Northwest forest fire. Changes in nitrogen levels following fire events. Spatial query of the ARC/INFO database of the dominant soil associations in the study sites within the MMF. Soil Classifications for each of the study pedons. Pedon 1 - Profile description, diagnostic horizons and/or properties typical of an Eluviated Dystric Brunisol found within the MMF. Pedon 1 - Selected physical and chemical properties of an Eluviated Dystric Brunisol found within the MMF. Pedon 9 - Profile description, diagnostic horizons and/or properties typical of an Orthic Humo-Ferric Podzol found within the MMF. Pedon 9 - Selected physical and chemical properties of an Orthic Humo-Ferric Podzol found within the McGregor Model Forest. Pedon 5 - Profile description, diagnostic horizons and/or properties typical o f an Orthic Gray Luvisol found within the MMF. Pedon 5 - Selected physical and chemical properties of an Orthic Gray Luvisol found within the McGregor Model Forest. Pedon 11 (lower slope) - Profile description, diagnostic horizons and/or properties typical o f a Rego Humic Gleysol found north o f the MMF. Pedon 11 (lower slope) - Selected physical and chemical properties of a Rego Humic Gleysol found north o f the MMF. Mean values of the results obtained finm the nitrogen analyses for each study site. Kruskal-Wallis H-Tests and Fisher’s LSD Tests for significant differences of the ranked mean nitrogen levels between age classes for each forest floor and mineral horizon using a 95% confidence interval. Results of the General Linear Model examining the interaction effect between soil horizons and age classes using a 95% confidence interval. -vni- 5 9 14-17 20 22-23 31 33 34 35 36 42 47-48 63 64 68 69 74 75 79 80 83 84 86 87 87 LIST OF TABLES (cont.) 5.14 5.15 5.16 5.17 5.18 5.19 5.20 5.21 5.22 Minimum, maximum, mean and standard deviations o f Total N contents (%) by horizon and age class. Minimum, maximum, mean and standard deviations o f available NO^ contents (ppm) by horizon and age class. Minimum, maximum, mean and standard deviations o f available N H / contents (ppm) by horizon and age class. Minimum, maximum, mean and standard deviations o f mineralizable N contents (ppm) by horizon and age class. Comparison of mineralizable N results between the F and H horizons. Mean mineralizable N per site as a weighted composite o f the A and B horizon results. Minimum, maximum, mean and standard deviations o f C/N ratio by horizon and age class. Mean percent vegetation coverage by plant type and forest age class. Areal coverage o f nitrogen projected areas within the MMF. -IX - 89 92 93 99 101 102 105 108 Ill LIST OF FIGURES 2.1 2.2 2.3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 5.1 5.2 5.3 5.4 5.5 5.6 Locations o f study sites in and around the McGregor Model Forest. Mean monthly temperature values fisr selected sites in the McGregor Model Forest and surrounding area. Monthly mean precipitation values for selected sites in the McGregor Model Forest surrounding area. Schematic illustration o f ground, surface and crown fire locations. Effects of temperature on selected soil constituents. Relationship between fire duration and moisture content to the amount o f resources consumed. 1951-1991 fires greater than 10 ha within the McGregor Model Forest. 1951-1991 fires in the SBSvk within and immediately surrounding the McGregor Model Forest. 1951-1991 fires in the SBSwk within and immediately surrounding the McGregor Model Forest. 1951-1991 fires in the SBSmk within and immediately surrounding the McGregor Model Forest. Possible direct and indirect effects of fire on nutrient cycling in northern ecosystems. Loss o f soil nutrients at various temperatures. Profile o f Pedon 1, an Eluviated Dystric Brunisol. Profile of Pedon 9, an Orthic Humo-Ferric Podzol. Profile o f Pedon 5, an Orthic Gray Luvisol. Profile o f Pedon 11 (lower slope), a Rego Humic Gleysol. Boxplot o f the A horizon NO] levels with the Early Serai (1), Mid-Seral (2) and Late Serai (3) age classes on the x-axis and the N O / levels (ppm) on the y-axis. Projection of Nitrogen Concentrations within the SBSvk Subzone of the McGregor Model Forest. -X - 11 12 12 26 27 30 32 37 38 39 40 41 67 73 78 82 95 112 ACKNOWLEDGEMENTS I would like to thank my supervisor, Dr. Lito Arocena, for his patience, understanding and assistance over the past two years. Also, thanks to the other members o f my committee. Dr. Hugues Massicotte for his advice along the way. Dr. Roger Wheate for his help and sense o f humour and Dr. Brad Hawkes for making me see that there’s more to fire than smoke. Much appreciation goes to Dr. Paul Sanborn for his valuable comments as the external reviewer to my thesis. I am also grateful to Dr. Bruno Zumbo for his assistance with my statistical analysis. Enormous personal gratitude goes out to Quentin Baldwin and Ed Stafford who saw me through some crazy times and helped keep me somewhat sane to the end. We’ll have to do another Hawaii when we’ve all made it to the real world. Thanks to all the technicians at UNBC who put up with me while I was establishing my territory in the lab building and for their work in the central equipment lab: Jill Craig, Richard Crombie, David Dick, Peter McEwan and a special thanks to Jennifer Wilson who lent me an ear on more than one occasion on top o f everything else. My gratitude to the GIS crew at the McGregor Model Forest Association who punched out maps when I couldn’t do it at UNBC: Morgan Cranny, Kate Sherren, Eric Valdai and Adrian Watson. Also, thanks to Glen Singleton who helped with posters and other presentation materials. I would like to extend my appreciation to the McGregor Model Forest Association and Northwood Pulp and Timber Limited who funded and provided logistical support for the project. Without their assistance, I would never have made it this far. Good luck to all other grad students at UNBC, especially those in the Faculty o f Natural Resources and Environmental Studies. You guys made this whole experience livable. -X I- Chapter One - INTRODUCTION 1.1 Rationale Forestry is vital to the economic future o f the central interior o f British Columbia. If it is not managed in a sustainable manner, the livelihoods o f many people will suffer. Forest soil, in addition to being a key attribute in determining the ecological quali^ o f a forest site, is essential to the sustainabUity o f timber extraction and forest productivity and is not renewable in the short-term (Kimmins, 1997; Klinka et a l, 1994). Knowledge o f soil properties is critical in the short and long term planning o f forest industry operations such as harvest scheduling and conservation plans, as is the soil’s capacity for recovery of its nutrient base following forest fires and other disturbances (K im m in s, 1996). Information regarding soils in the Prince George Forest Region is very sparse. The British Columbia Soil Survey is far firom complete and does not provide sufficient information upon which management decisions may be made (Driscoll, 1996). Forest floor and soil survey data (combined with information on the nitrogen characteristics o f the dominant horizons therein) may be used in assessing the nitrogen fertility of different ecosystems (Fyles et ai, 1991b). By presenting baseline information on the types of soils foimd in this region and the levels o f nitrogen, perhaps the most limiting o f nutrients in British Columbia’s Central Interior, forest practitioners in this region have more information upon which to base forest management decisions. Two phases o f analysis are used in the presentation of my research: (1) classification o f the soils, and; (2) quantification of the concentrations of the various forms o f nitrogen (total nitrogen, carbon/nitrogen ratio, available ammonium and nitrate, mineralizable nitrogen). The classification phase describes the soils that are found within the very wet, cool Sub-boreal Spruce biogeoclimatic subzone (SBSvkl) within the McGregor Model Forest. The soils are classified to the subgroup levels with full physical, chemical and morphological data provided. The second phase examines nitrogen dynamics as they occur following stand replacement by forest fires. A retrospective approach is used which presents patterns of change in nitrogen levels as the forest undergoes succession. Since soil survey information is a critical component o f land management decisions that use geographic information systems (GIS) (Maclean et a l, 1993), available information has been digitized and is presented as an ARC/INFO database in this thesis. However, much o f this information is presented in medium scale maps, generally between 1:100,000 and 1:250,000 (e.g. Dawson, 1989), which cannot account for the heterogeneity o f the soils being described. This study also expands upon this knowledge base by providing ground-proofed, site-specific data through the classification of pedons fi*om the 13 study sites using the Canadian System of Soil Classification (Canadian System) and the USDA Soil Taxonomy (Soil Taxonomy). The primary advantage o f the Canadian System is its bias towards soil genesis; the names o f the orders provide natural groupings o f soils with similar characteristics and properties (Agriculture Canada Expert Committee on Soil Survey, 1987). The Soil Taxonomy, which is similar to the Canadian System, uses a taxonomic approach to soil classification which provides detailed descriptions o f the soils within their classification names (Soil Survey Staff, 1994). This system is widely used in the United States and outside North America by countries which do not have their own system o f soil classification since it can be used in the classification o f all types of soil, whether or not found in the United States (Buol et al, 1989; Soil Survey Staff, 1994; Yaalon, 1995). This thesis will help to illustrate the important role fire plays in nutrient cycling in northern coniferous forests and its effect on nitrogen levels on tlie forest floor and within the mineral horizons. In a region which reUes heavily on the sustainable growth of trees for economic survival, increased -2 - knowledge of nitrogen cycling can aid in determining which management practices are sound and should be followed. For example, linking the length o f time following a forest fire to nitrogen levels may aid in determining the most ^propriate time for planting or in preparing the appropriate nutrient mixture for the seedling plugs. As an essential nutrient, nitrogen is vital to the development o f all plants; it is an integral component of chlorophyll and enzymes, a component of amino acids and the proteins required for the genetic development of plant tissue, cell nuclei and protoplasm (Brady, 1990). In boreal and cool temperate forests, nitrogen may be deficient because o f slow decomposition, mineralization and cycling caused by low soil temperatures or poor drainage (Kimmins, 1996). Few studies have investigated nitrogen cycling in the central interior of British Columbia resulting in a paucity o f data fi’om which to assist in forest management decisions. The relationships between the various soils and the levels o f different nitrogen forms for each site should lead to a projection of nitrogen activity in similar areas within the model forest region. A j cursory examination o f the variations found in the different levels o f nitrogen based on the vegetation present at the study sites is also undertaken. It is believed that the relationship between vegetation species composition and nitrogen turnover should be fairly constant within an ecosystem (Zak et a i, 1986), thus allowing for the extrapolation of data fi’om point sources to a landscape level. By conducting nitrogen analyses on selected sites within the very wet, cool Sub-boreal Spruce biogeoclimatic subzone, it should be possible to present a picture of the nitrogen dynamics within these areas. -3- 1.2 13 Research Objectives 1. To determine the physical, chemical and morphological characteristics o f selected postforest fire soils within the SBSvkl in the McGregor Model Forest in order to classify them according to the Canadian System o f Soil Classification (Agriculture Canada Expert Committee on Soil Survey, 1987) and the Keys to Soil Taxonomy (Soil Survey Staff, 1994) and compare their properties with other soils. 2. To determine the contents o f total N, mineralizable N, available ammonium and nitrate o f the forest floor and mineral horizons in order to determine the site quality of each soil and to investigate post-fire soil nitrogen dynamics as related to forest stand age. Research Hypotheses Results o f the soil classification will be based on descriptive data obtained through field descriptions and laboratory analyses. The nitrogen analyses will include a presentation o f the data obtained as well as an investigation o f the content o f total nitrogen, potential mineralizable nitrogen, available ammonium and available nitrate within the mineral and forest floor horizons of selected post­ fire soils. The interaction between horizons and age classes is also investigated. The hypotheses are: Ho,: There is no difference in total nitrogen, mineralizable nitrogen, available ammonium and nitrate, levels between the different age classes o f each horizon. Ha,: There is a significant difference in total nitrogen, mineralizable nitrogen, available ammonium and nitrate, levels between the different age classes o f each horizon. Ho.: There is no interaction between the content o f total nitrogen, mineralizable nitrogen, available ammonium and available nitrate levels o f the mineral and forest floor horizons and the different age classes. H a .: There is a significant interaction between the content o f total nitrogen, mineralizable nitrogen, available ammonium and available nitrate levels o f the mineral and forest floor horizons and the different age classes. -4- I Chapter Two - STUDY AREA AND CHARACTERISTICS The study sites are located on the McGregor Plateau in the Central Interior o f British Columbia Details of the locations o f the study sites have been provided in Table 2.1. This sub-boreal, montane area is bounded to the east and north by the Rocl^ Mountains, to the west by the Fraser Basin and to the south by the Nechako Plateau. The surficial geology, soil series, vegetation inventory and biogeoclimatic classification o f the sites are described in this chapter. Table 2.1 Latitude (N) Longitude (W ) Elevation (m.a.s.1) Slope Aspect ( • /.) O 1 54‘^0.2 122=10.6 930 50 164 2 54°20.2 122=10.6 54“19.5 122=15.2 15 37 194 3 940 820 4 54°21.7 121=59.9 30 32 5 54“23.7 122=13.5 870 1010 63 230 6 7 54“23.7 122=13.6 54“20.2 122=12.0 1010 1070 58 5 60 250 8 54°24.0 1040 9 10 54=05.7 122=13.5 121=29.3 1020 37 34 54=22.8 54=44.1 122=08.6 122=12.8 850 1160 290 200 50 180 54=44.2 54=08.8 122=12.2 1160 890 S ite# 11 12 13 2.1 Locations of study sites, 121=10.9 16 50 50 55 0 180 0 Surficial Geology This study area has undergone many changes since the beginning o f the Pleistocene (c. 1.65 Ma - 10 ka). Little now remains o f the Pleistocene sediments within the interior o f British Columbia as they are generally considered to have been scoured away during the advance and 5 retreat o f the ice sheet and glaciers o f the Fraser Glaciation (c. 23-10 ka) or are covered by thick drift (Clague et al., 1990). Pleistocene sediments are generally found in areas where bedrock projections deflected glacier advances and retreats, thus sheltering downstream areas from glacial scouring. Sedimentary layers along the margins o f glaciers and the Cordilleran Ice Sheet also may have been protected because o f the sluggish ice flow in the areas (Ryder and Clague, 1989). Much o f the surficial material currently found within the interior o f British Columbia is the result of sediments and till laid down at the close o f the Fraser Glaciation. The primary sources o f this material were the Rocky and Mackenzie Mountains (Clague, 1989c). The three major different types o f surficial material o f the study area are: glacial lacustrine, glacial fluvial and colluvium. These are all common to the Cordillera. Glacial lacustrine deposits are remnants o f glacial lakes which had received outwash from glacial streams. The sediments which are indicative o f a glacial lacustrine past are well stratified and include fine sand, silt and clay. Well defined stratification of this material is demonstrative o f a process o f sedimentation occurring during relatively stable conditions (Clague, 1989a). Glacial fluvial deposits are formed by streams which were established from glacial meltwater. Features such as kames, kame terraces, kettle lakes and eskers are all indicative o f a glacial fluvial history and are found in many areas within the McGregor Model Forest. Glacial fluvial deposition may be distinguished by thin continuous sheets o f gravel and sand overlying a layer o f till. Glacial fluvial layers also may be found beneath till layers in cases where evidence o f older Pleistocene glaciations are still prevalent (Clague, 1989b) Colluvial deposits occur as a result o f mass wasting processes and are commonly found as -6“ surficial material in the Cordilleran region o f British Columbia. Clague (1989a) discussed four major types o f colluvium which are indicative o f the central interior: landslide deposits, talus, colluviated drift and solifluction. The landslide deposits and colluviated drift are o f particular interest as these features are found at our study sites. Landslide deposits have the greatest variation o f texture and mass o f the different colluvial deposits. They may occur as fine grained material from glacial lacustrine sediments or as coarse, blocky accumulations o f broken rock. While landslides may occur in any part o f the Cordillera, they tend to be relatively small in total size, representing less than one percent o f the total surface area. Colluviated drift is a glacial deposit which has been transformed by sheet erosion and creep. This material forms thin mantles of diamicton and poorly sorted gravel on moderate and steep slopes. Areas o f colluvial drift do exist within the area, however, our observations agreed with those o f Clague (1989a) in that the colluvial deposits exist as secondary features within the bounds of other more dominant forces. 2.2 Soil Series of the Study Areas Examination o f 1:50,000 soils and surficial geology/landform maps indicated that the 13 study sites belonged to 10 different soil associations on four different map sheets. The locations and selected properties of these associations are provided in Table 2.2. The map provided as Appendix A shows the locations o f the soil complexes within the McGregor Model Forest. Sites 1,2, 3,4, 5, 6,7 and 8 belong to a combination o f the Averil and Dominion Soil Series (Dawson, 1989; Ministry of Forests, 1977). Averil Association soils are shallow soils o f the Fraser Plateau dominated by Orthic Humo-Ferric Podzols. Gravelly sand is common (Dawson, 1989; Ministry o f Forests, 1977; Watt, 1980). The Dominion Association is also formed upon glacial materials. Dominion Soils are generally gravelly and loamy having developed on morainal materials. These soils are well drained and classified as Luvisolic Humo-Ferric Podzols (Lord, 1984; Watt, 1980). Sites 10 and 13 were mapped as part o f the Captain Creek Association in combination with other soil series. These are loamy soils developed on morainal materials. These soils are moderately well drained and have perhumid moisture regimes. Orthic Humo-Ferric Podzols are common as well as Podzolic Gray Luvisols to a lesser extent (Dawson, 1989; Lord, 1984; Ministry of Forests, 1977; Watt, 1980). The other series in combination with the Captain Creek Association at Site 10 is the Bearpaw Ridge Association. These sandy and loamy soils developed on colluvial deposits and are moderately well drained occurring under humid moisture conditions. Orthic Humo-Ferric Podzols again are the dominant classification, however, Eluviated Dystric Brunisols are also common (Dawson, 1989; Lord, 1984; Ministry of Forests, 1977). At Site 13, the Dezaiko Association occurs with the Captain Creek Association. The Dezaiko Association is characterized by loamy and sandy soils developed on shallow colluvial or morainal deposits. These soils are well to moderately well drained and have humid to subhumid moisture conditions. They are found at higher elevations, generally above 1500 metres. Again, Orthic Humo-Ferric Podzols are the common classified soils (Lord, 1984; Watt, 1980). Sites 11 and 12 belong to the Barton Soil Series which is characterized by Orthic FerroHumic Podzols formed o f rubbly, silty colluvium occurring at various depths over metamorphic rock (Ministry o f Forests, 1977). -8- Table 2.2 Soil associations and selected properties determined for each of the study sites. Site 1 2 3 4 S 6 7 8 9 10 Soil A ssociations Dominion 2 (80% ) Dominion 2 (80%) Dominion 2 (60% ) Dominion 2 (70% ) Averil 1 (70%) Averil 1 (70% ) Averil 1 (80%) Averil 1 (70%) Torpy River 2 (50% ) Averil 1 (20%) Averil 1 (20%) Averil 1 (40%) Averil 1 (30%) Dominion 2 (30%) Dominion 2 (30% ) Dominion 2 (20%) Dominion 2 (30% ) Dome Creek 1 (50% ) Bearpaw Ridge (70% ) Captain Creek (30%) N TS M ap A R C /IN F O Polygon D om inant C lassification P a re n t M ateria l P a rtic le Size C lass D rainage 93J/8 260 P.GL/O.HFP morainal/ colluvial gravelly loam/ moderately well gravelly sand to well morainal/ colluvial gravelly loam/ moderately well gravelly sand to well morainal/ colluvial gravelly loam/ moderately well gravelly sand to well morainal/ colluvial gravelly loam/ moderately well gravelly sand to well colluvial/ morainal gravelly sand/ moderately well gravelly loam to well colluvial/ morainal gravelly sand/ moderately well gravelly loam to well colluvial/ morainal gravelly sand/ moderately well gravelly loam to well colluvial/ morainal gravelly sand/ moderately well gravelly loam to well morainal/ colluvial gravelly loam/ moderately well loam to rapid colluvial/ morainal gravelly sandy loam/ gravelly loam moderately well 93J/8 93J/8 931/5 93J/8 931/8 93J/8 93J/8 931/3 93J/8 260 203 118 232 232 216 232 15 257 P.GL/O.HFP P.GL/O.HFP P.GL/O.HFP O.HFP/P.GL O .HFP/P.GL O.HFP/P.GL O .HFP/P.GL O .HFP/E.DYB O.HFP well to 11 Barton 5 (100% ) 93J/9 n/a O.FHP colluvial rubbly silt moderately well 12 Barton 5 (100%) 93J/9 n/a O.FHP colluvial rubbly silt moderately well 13 Dezaiko 2 (60%) 931/3 n/a O.HFP colluvial/ morainal gravelly sandy loam/ well to gravelly loam moderately well Captain Creek 2 (40% ) from Dawson, 1989; Driscoll, 1996; Lord, 1984; Ministry o f Forests, 1977; Watt, 1980, E.DYB = Eluviated Dystric Brunisol, 0 , FHP = Orthic Ferro-Humic Podzol, O .HFP = Orthic Humo-Ferric Podzol, P, GL = P'odzolie Gray Luvisol Site 9 is a combination o f Dome Creek and Torpy River Soil Associations. The Torpy River Association has developed gravelly and loamy soils on morainal materials. While Orthic HumoFerric Podzols are foimd in the well to moderately well drained areas, gleyed soils and Ferro-Humic Podzols may also be foimd (Lord, 1984; Watt, 1980). 2.3 BiogeocUmatic Ecosystem Classification The study sites are located within the McGregor Model Forest in the Sub-boreal Spruce (SBS) biogeoclimatic zone. The locations o f our study sites and the different biogeoclimatic subzones within the McGregor Model Forest are indicated in Figure 2.1. (Note: Due to mapping limitations, sites 9 and 13 appear to be within the ICH biogeoclimatic zone, however, site indicators were representative o f the SBSvk and this becomes apparent on a larger scale map.) The SBS zone is dominated by gently rolling montane terrain o f the Nechako and Fraser plateaus as well as the Fraser Basin. The maximum elevation ranges are between 1100-1300 m.a.s.l. where the Engelmann Spruce-Subalpine Fir (ESSF) zone begins (Meidinger et a i, 1991). This zone is characterized by seasonal extremes in temperature with severe winters and warm summers; the mean annual temperature ranges from 1.7-5°C. Precipitation is moderate ranging from 440-900 mm with 2550% falling as snow. Monthly normals for temperature (Figure 2.2) and monthly normals for precipitation (Figure 2.3) have been compiled from the Environment Canada Climate Normals for four weather stations within this zone: Aleza Lake, McGregor, McLeod Lake and Prince George International Airport (Environment Canada, 1982). Note that the mean monthly temperatures are below the freezing point for five months of the year and that this is the same period in which the -10- Igure 2.1 Location of study sites in and around the McGregor Model Forest mtOm Locations of Study Sites in and around the McGregor Model Forest Sub-BoM Spnio* ■SBS vk Stib-BonMl SpniM - SBS wk Sub-BiNMl Bpnioa - SBS mk SMb-BeiMl 8| num ■BBS mh Sub-BeiMl SpruM - SBS dw Engalmann Spnioa/Sub-AlpkMi Hr - ESSF wk EngtbnMNi Spruea/Stib-Alpbw Hr- ESSF mv InW or Cadw/HwnloGk - ICH vk kiM or Cadw/Hwniook - ICH wk Bo im I WhIW wid Btaok Sprue* - BMVBS wk BotmI WhHi ami Black Sprue* - BIMBS mw Alptiwlundra-AT SturlyMntB Seal# 1:700 000-KHomBliM 0##»# IW M c te M a M ta l 41» Figure 2.2 Mean monthly temperature values for selected sites in the McGregor Model _____________Forest and surrounding area. U II I II H -10 -15 o Figure 2.3 JAN FEB MAR Aleza Lake APR MAY JUN McGregor JUL AUG SEP McLeod Lake OCT NOV DEC Prince George Monthly mean precipitation values for selected sites in the McGregor Model Forest and surrounding area. 120 100 o. JAN Aleza Lake FEB MAR APR MAY JUN JUL AUG McLeod Lake McGregor -1 2 - SEP OCT NOV DEC Prince George highest precipitation means are recorded, predominantly as snow. M ore specifically, the study sites were located in the very wet, cool Sub-boreal Spruce biogeoclim atic subzone (M eidinger and Pojar, 1991; Pojar et al., 1987). The soil moisture and temperature regimes are categorized as humid to subhumid cryoboreal (Clayton et al., 1977). The dominant soils in the SBS are Luvisols, Podzols and Brunisols. Imperfectly drained areas may be characterized as Gleysols (M eidinger et a i, 1991). The SBSvk 1 subzone typically is characterized by devil's club (Oplopanax horridus) and leafy mosses (Mnium spp.) with an overstory o f hybrid white spruce (Picea glauca x engelmartnii). Other indicator species o f this zone are oak fern (Gymnocarpium dryopteris), thimblebeny (Rubus parviflorus), five-leaved bramble (Rubus pedatus) and three-leaved foamflower (Tiarella trifoliata)(JS/leidingQx et al., 1991). All vascular plant species and bryophytes occurring in the 30 x 30 m plots o f study sites 1 - 1 2 were recorded as a percent o f area covered by the McGregor Model Forest Ecological Processes Team and are presented in Table 2.2. (Site 13 was selected to fulfill statistical requirements for the soil nitrogen analysis and was not necessary for the vegetation inventory and, thus, no species list is available.) - 13- Table 2.3 Inventory of vegetation for sites 1-12. Values presented as a percentage of the area covered of the study quadrats. Early Serai Trees Sites Mid-Seral Site 6 Site 9 S ite l Late Serai Site 3 Site? Site 10 Site 11 Site 2 Site 4 S ites Site 12 Abies lasiocarpa (Hook.) Nutt. •** 0.1 5 5 5 20 2 20 15 30 2 Picea glauca (Moench) Voss x Picea engelmamii Pany ex Engelm. 0.1 20 15 40 40 10 50 25 54 30 Populus tremuloides Michx. 1 Betula p c^rifera Marsh. 1 Shrubs Abies lasiocarpa (Hook.) Nutt. 0.1 5 Acer glabnm Ton. Actaea rubra (Ait.) Willd. 10 1 3 1 1 Alnus tenuifolia Nutt. 15 0.1 1 5 0.1 10 15 3 0.1 1 2 2 0.1 1 3 2 0.5 1 Betuia papyri/era Marsh. 3 Cornus stolonifera Michx. 0.5 2 2 Oplopanax horridum (Smith) Miq. 0.1 3 Picea glauca (Moench) Voss x Picea engelmannii Parry ex 0.1 Engelm. 15 10 Lonicera involucrata (Rich.) Banks 7 Populus tremuloides Michx. 0.5 Rhododendron albiflorum Hook. 15 Ribes lacustre (Pers.) Poir. 2 Ribes laxiflorum Pursh 2 5 Amelanchier alnifolia Nutt. Aruncus dioicus (Walt.) Fern, 5 1 5 3 3 3 2 1 3 3 70 20 30 70 3 5 2 5 0.5 1 1 2 65 4 2 0.5 0.1 0.5 2 20 1 Ribes oxyacanthoides L. 0.1 Rosa acicularis Lindl. 6 0.1 Rubus idaeus L. 3 2 5 Rubus parviflorus Nutt. 35 7 20 10 10 5 5 1 5 0.1 Rubus pubescens Raf. 10 Salix spp. Sambucm racemosa L. 3 Sorbus scopulina Greene 0.1 2 0.1 1 1 2 2 1 7 5 1 1 3 1 1 1 2 7 0.1 1 Spiraea betulifolia Pall. 0.1 Spiraea douglasii Hook. 1 Thuja plicata Bonn. 3 Vaccinium membranaceum Dougl. Vaccinium ovalifoiium Smith 1 Viburnum edule (Michx.) Raf. 0.1 2 20 25 25 0.5 1 30 40 30 1 2 2 1 0.1 7 0,1 1 1 15 10 0,1 1 0.1 5 0.1 0.1 Herbs Aconitum delphiniifolium DC. Anaphalis margaritacea (L.) B. & H. 0.1 1 5 20 Aguilegiaformosa Fisch. 0.1 Aralia nudicaulis L. 0.1 2 A tf^iu m filix-femina (L.) Roth. Calamagrostis canadensis (Michx.) Beauv. 0.1 7 5 6 1 10 10 2 Calamagroslis rubescens Buckl. Carex merlensii Prescott 6 2 3 5 0.5 2 0.1 Carex spp. Castilieja miniata Dougl. 0.1 Cinna latifolia (Trevir.) Griseb. 3 0.1 CircaeaalpinaL. 0.1 1 Cirsium arvense (L.) Scop. 0.1 Clintonia uniflora (Schult.) Kunth. 3 1 Cornus canadensis L. 2 2 2 Danthonia intermedia Vasey 5 0.1 1 3 3 3 5 10 10 15 2 3 1 1 9 1 Disporum hookeri (Torr.) Nicholson Drvopteris assimiiis S. Walker 1 4 2 3 0.1 2 20 3 20 20 20 Dryopteris expansa (K.B. Presl) Fraser-Jenkins & Jermy Epilobium anguslifolium L. 6 60 Equisetum arvense L. 55 60 0.1 0.5 0.1 0.1 0.1 0.5 Equisetum sylvaticum L. 0.1 3 2 1 3 Goodyera oblongifolia Raf. Gymnocarpium dryopteris (L.) Newm. 0.5 1 1 35 60 0.5 2 30 2 3 2 15 15 Heracleum sphomfylium L. 5 10 0.1 Hieracium aurantiacum L. 0.5 3 0.1 2 Hieracium tmbellatum L. 0.1 Listera cordata (L.) R. Br. 0.1 0.1 Lycopodium annotinum L. 2 Orthilia secunda (L.) House 0.1 0.1 0.1 0.5 Osmorhiza purpurea (Coult. & Rose) Suksd. 0.1 0.1 0.1 Pteridium aquilinum (L.) Kuhn. 1 Rubus pedatus J.E. Smith 1 5 Senecio triangularis Hook. 23 0.5 Smilacina racemosa (L.) Desf. 1 Streptopus amplexifolius (L.) DC. 1 Streptopus roseus Michx. 3 1 1 1 5 2 2 1 2 1 1 4 1 5 15 0.1 0.1 1 1 1 0.1 0.5 0.1 0.1 3 Thalictrum occidentale Gray 1 3 2 2 0.1 4 2 10 1 Thalictrum venulosum Trel. 0.1 0.1 Thalictrum spp. 1 0.1 0.1 Tiarella trifoliata L. Tiarella unifoUata (Hook.) Kurtz. 0.1 0.1 Osmorhizd chilensis H. & A. Plalanthera obtusata (Banks ex Pursh) Lindl. 0.1 0.5 Hieracium albiflorum Hook. Hieracium gracile Hook, 0.1 0.1 Equisetum pratense Ehrb. Galium triflorum Michx. 0.1 1 1 3 2 3 7 0.1 2 5 12 1 1 5 Urtica dioica L. 1 Valeriana sitchensis Bong. Veratrum viride Ait. 15 Viola adunca Sm. 10 1 2 0.1 10 20 1 0.1 5 2 2 7 5 0.1 0.1 0.1 Viola canadensis L. Viola glabella Nutt. 0.1 1 0,1 Viola spp. L. 0.1 0,5 Mosses Brachythecium hyhtapetum B. Hig. & N.Hig. 5 1 10 Brachythecium oedipodium (Mitt.) Jaeg. & Sauerb. 5 Brachythecium spp. 5 Dicranum fitscescens Sm. 0.1 0.1 Hylocomium splendens (Hedw.) B.S.G. 5 Lycopodium annotinum L. 0.1 0.1 1 1 Marchantia polymorpha L. Mnium spp. 5 Plagiomnium drummondii (Bruch & Schimp.) Kop. 0.1 25 Plagiomnium spp. Pleurozium schreberi (Brid.) Mitt. Ptilium crista-castrensis (Hedw.) Rhytidiadelphus triquetrus (Hedw.) Wamst. Rhizomnium glabrescens (Kindb.) Kop. 1 5 Plagiomnium insigne (Mitt.) Kop. Polytrichum Juniperinum Hedw. 0.1 20 10 15 20 5 5 3 5 5 5 70 30 0.1 8 20 30 3 3 5 authorities based on: Brayshaw, 1996; Douglas e/a/., 1989; Douglas et a/., 1990; Douglas e/a/., 1991; Douglas e/o/., 1994; Hitchcock and Cronquist, 1973; Schofield, 1992; Vitt et al., 1988. Chapter Three - REVIEW OF LITERATURE This chapter presents a review o f current knowledge and information pertinent to the work conducted in this thesis. The first three sections provide a brief background behind the classification o f the study pedons. The general rationale behind soil classification and the different systems used are followed by more specific information currently available about the soils o f the McGregor Model Forest. The remainder o f this chapter focuses on the role o f fire on soils and soil nutrient cycling. Fire history information for the study area has also been provided. 3.1 Classifying Soils Classification o f the selected pedons allows for the systematic recollection and dissemination o f knowledge o f the soils being studied in an organized manner which may be communicated to others discussing soils (Agriculture Canada Expert Committee on Soil Survey, 1987). The historical record o f attempts at differentiating between soils has been traced back over 4000 years with the early work o f the Chinese (Steila and Pond, 1989). In their treatise, Baldwin et al. (1938) provided the essence o f soil classification during its early development, “Man has a passion for classifying everything. There is a reason for this; the world is so complex that we could not understand it at all unless we classified like things together. Just as plants, insects, birds, minerals, and thousands o f other things are classified, so are soUs.” 3.2 Taxonomic Systems o f Classification Taxonomic systems are based on the natural characteristics o f Wratever is being classified. With -1 8 - soils, these properties may include: texture, colour, structure and aggregation, mineralogy, soil temperature and moisture (and how these properties change throughout the year), cation exchange capacity and exchangeable cations, base saturation, site drainage, pH, as well as other properties which may be distinctive to different locations (Agriculture Canada Expert Committee on Soil Survey, 1987; Fanning and Fanning, 1989; Soil Survey Staff, 1994). The two systems used in this thesis were the Canadian System o f Soil Classification, Second Edition (Agriculture Canada Expert Committee on Soil Survey, 1987) and the United States Department o f Agriculture’s (USDA) Keys to Soil Taxonomy. Sixth Edition (Soil Survey Staff, 1994). 3.2.1 Canadian System o f Soil Classification Soil surveys have been carried out in Canada since 1914. Since that time, several changes and refinements have occurred to the ways in \\irich soil classifications are conducted. The Canadian System o f Soil Classification (Canadian System) is currently being used by Canadian pedologists and others describing soils in Canada. The Agriculture Canada Expert Committee on Soil Survey (1987) listed six attributes which they felt were the basis upon which the Canadian System was developed: 1. 2. 3. 4. 5. 6. It provides taxa for all known soils in Canada. It involves a hierarchical organization o f several categories to permit the consideration o f soils at various levels o f generality. Classes at high categorical levels reflect, to the extent possible, broad differences in soil genesis. The taxa are defined specifically so as to convey the same meaning to all users. Tire taxa are concepts based upon generalizations o f properties o f real bodies o f soils rather than idealized concepts o f the kinds o f soils that would result firom the action o f presumed genetic processes. Differences among the taxa are based upon soil properties that can be observed and measured objectively in the field or in the laboratory. It is possible to modify the system on the basis o f new information and concepts without destroying the overall framework. - 19- The hierarchical ^ p ro ach used by the Canadian System breaks into five categorical levels: order, great group, subgroup, family and series. Table 3.1 provides a breakdown o f the differentiating criteria o f each o f these levels. Table 3.1 Defining taxa for the various categorical levels within the Canadian System of Soil Classification. Categorical Level Differm tiatiiig Criteria Order * nature o f the soil environment * effects o f the dominant soil-forming processes Great Group * properties that reflect differences in the strengths o f the dominant processes Subgroup * type or arrangement o f the horizons Family * parent material characteristics Series * detailed features o f the pedon 3.2.2 USD A Soil Taxonomy Similar to the Canadian System, the USDA Keys to Soil Taxonomy (Soil Taxonomy) uses a hierarchical approach to classifying soils. The major differences are the inclusion o f the Cryosolic, Gleysolic and Solonetzic orders within the Canadian System and the incorporation o f the suborder category in Soil Taxonomy (Agriculture Canada Expert Committee on Soil Survey, 1987; Soil Survey Staff, 1994). While Soil Taxonomy lias been created with a bias towards soil genesis, an agricultural emphasis also has been stressed (Fanning and Fanning, 1989). Soil Taxonomy was devised with 10 soil orders breaking down into 47 suborders, 241 great groups and 1500 subgroups. Further subdivision may be made to the family and soil series levels. Since this system was devised to accommodate all types of soils, it has become widely used by those studying soils in countries which do not have their own soil -2 0 “ classification systems (Buol et al., 1989). 3.3 Soils of the McGregor Model Forest A soil association is a sequence o f soil series o f similar age which were developed upon similar parent material imder similar climatic conditions (Agriculture Canada Expert Committee on Soil Survey, 1987). The McGregor Model Forest landscape is composed o f 27 soil series, including: Averti, Bearpaw Ridge, Bednesti, Bowron, Captain Creek, Chief, Cobb, Deserters, Dezaiko, Dome Creek, Dominion, Fontoniko, Fraser, Giscome, Gunniza, Hah Creek, McGregor, Merrick, Moxley, Paxton, Pineview, Ramsey, Rockland, Seebach, Spakwaniko, Stellako and Torpy River (Dawson, 1989; Driscoll, 1996; Lord, 1984; Ministry o f Forests, 1977; Watt, 1980). Table 3.2 summarizes the major properties of the soil series found within the McGregor Model Forest. 3.4 Ecological Role of Fire Fire has played an integral role in nutrient cycling and stand replacement in Canada since the Miocene (7 Ma B.P.) (Weber and Taylor 1992). In 1973, it was estimated that 0.3% o f the country’s forest area bums every year (Rowe and Scotter, 1973), that figure has been revised to 0.6% o f Canada’s forests (Simard, 1997). In fact, it also has been estimated that double this amount, or 1.0 - 1.3% o f Canada’s forested land would bum armually if not for fire suppression activities (Simard, 1997). Fire continues to be a dominant factor in the Sub-Boreal Spruce (SBS) biogeoclimatic zone o f British Columbia Factors such as fire intensity, fire temperature, vegetation types, amounts and types o f firels, topography, micro- and meso-climates all play different -2 1 - Table 3.2 Soil Series of the McGregor Model Forest Soil Series Physiogrmpbic SubdhiskMi Dominant Soil Type Averil Fraser Plateau, McGregor Plateau Bearpaw Ridge Common Texture Common Drainage Orthic Humo-Ferric Podzol sandy loam moderately well to well Fraser Plateau, McGregor Plateau, Rocky Mountains Orthic Humo-Ferric Podzol sandy loam well Bednesti Fraser Basin, Nechako Plain Brunisolic Gray Luvisol silt loam moderately well Bowron Fraser Basin, McGregor Plateau Brunisolic Gray Luvisol silt loam moderately well Captain Creek Quesnel Highland, McGregor Plateau, Rocky Mountains Orthic Humo-Ferric Podzol sandy loam moderately well Chief Fraser Plateau Typic Mesisol fibric very poorly Cobb Fraser Plateau Orthic Humo-Ferric Podzol sandy loam well Deserters Fraser Plateau Brunisolic Gray Luvisol loam moderately well Dezaiko Fraser Plateau, McGregor Plateau, Rocky Mountains Orthic Humo-Ferric Podzol sandy loam moderately well to well Dome Creek Rocky Mountain Trench, McGregor Plateau Eluviated Dystric Brunisol Dominion Fraser Plateau, Fraser Basin, McGregor Plateau Luvisolic HumoFerric Podzol loam moderately well Fontoniko Fraser Plateau, Quesnel Highland, McGregor Plateau Eluviated Dystric Brunisol sandy loam well to rapidly Fraser Nechako Plain Orthic Gray Luvisol silt loam moderately well Giscome Fraser Basin Orthic Dystric Brunisol loamy sand rapidly Gunniza Rocky Mountain Trench, Fraser Basin Orthic Humo-Ferric Podzol loamy sand rapidly -2 2 - rapidly to well Hah Creek McGregor Plateau Sombric HumoFerric Podzol McGregor Rocky Mountain Trench, Fraser Basin, McGregor Plateau Gleyed Regosol loam imperfectly Orthic Humo-Ferric Podzol. sandy loam well Merrick moderately well to imperfectly Moxley Roclqr Mountain Trench, Fraser Basin, McGregor Plateau Mesic Fibrisol fibric very poorly Paxton McGregor Plateau, Rocky Mountains Orthic Humo-Ferric Podzol loam well Pineview Fraser Basin Gleyed Gray Luvisol heavy clay imperfectly Ramsey Fraser Plateau Orthic Humo-Ferric Podzol loamy sand rapidly Seebach Fraser Plateau Orthic Humo-Ferric Podzol loamy sand well Spakwaniko Quesnel Highland, Cariboo Mountains Orthic Humic Gleysol sandy loam poorly Stellako Rocky Mountain Trench Gleyed Regosol sandy loam poorly to imperfectly Torpy River Fraser Plateau Orthic Humo-Ferric Podzol sandy loam moderately well rapidly drained = soil holds little moisture after rain, well drained = no excess moisture for most of the year, moderately well drained = excess moisture for a short but significant period of the year, imperfectly drained = soil remains wet in subsurface horizons for a moderately long period of the year, poorly drained = excess moisture throughout soil for a large part of the year, very poorly drained = ftee water remains at or within 30 cm of the surface most of tlie year from Dawson, 1989; Driscoll, 1996; Lord, 1984; Ministry of Forests, 1977; Watt, 1980 roles in determining how the fires will affect nutrient losses and nutrient cycling as well as the soils physical properties. Much o f the floral and faunal diversity in Canada’s boreal forests can be attributed to lightning and human-caused fires which affect ecosystem composition, soil chemical properties and temperature (Rowe and Scotter, 1973). In examining the fire history o f the Bowron Lake Park near Prince George, Parminter (1993) discussed the historical role fire has played, “Natural fire has served - 23 - to maintain a variety o f forest age classes on the landsc^)e, with each burned area containing a tree species mixture which reflects the site’s ecological characteristics, vegetative composition at the time o f the fire and post-fire conditions.” 3.5 Fire Causes and Patterns Forest fires may be caused by lightning, volcanic eruptions, sparks fiom falling rocks and even spontaneous combustion in marshy areas, as well as by human activities (Sousa, 1984). Lightningcaused fire fiequency in the southern Canadian Rockies has been characterized by few, infiequent large fires determining the forest age mosaic, i.e., 2% o f the lightning fires caused 95% o f the total area burned (Johnson and Outsell, 1994; Johnson and Wowchuk, 1993; Parminter, 1990). For all o f Canada’s forests, lightning is reported to cause 42% of all fires leading to 85% o f the area burned (Simard, 1997). Fire occurrences have been traced along shifting climatic regimes since the end of the last glaciation. Pollen and charcoal records indicate that fire patterns follow the changes in vegetation distribution which resulted from changes in climate (Edlund and Byrne, 1990). Examination o f fire fiequency records o f three national parks and a forest reserve within the southern Canadian Rockies indicated a fire return interval o f approximately 100 years over the 20,500 km- area examined (Johnson and Wowchuk, 1993). Their report shows periods in which weather patterns develop into high-pressure ridges within the troposphere stalling in the Rockies and preventing moist low-pressure systems fiom entering the regions. Since these blocking events are on scales of 100 km - 1000 km, this leads to a large scale drying o f the soil and vegetation and a condition conducive to large fires. Fire frequency patterns have changed considerably since the arrival o f European settlers to - 24- western North America. Fire exclusion together with grazing and timber harvesting have all led to changes in ecosystem structures, landscape patterns and disturbance regimes that are different from the patterns that have evolved with the indigenous biota (Covington et a i, 1994). However, these patterns vary considerably by ecosystem. For example, ponderosa pine communities in the American Inland West have been determined to have had historic low intensity fires at return intervals fi-om as little as 510 years to as much as 20-30 years, maintaining comparatively open, fuel-fi%e stands, compared to high intensity and stand replacing fires at intervals as long as 200+ years for higher elevation lodgepole pine/subalpine fir/Engelmann spruce forests (Mutch, 1994; Steele, 1994). The record o f all the fires which occurred in Canada between 1961 and 1967 showed that 85% o f the events were smaller than or equal to 4 ha (Rowe and Scotter, 1973) and another study shows the average fire size being 315 ha (Simard, 1997). In the case o f fire exclusion, a different plant succession can change the species composition and density beyond the historic range for these communities. Outbreaks o f insects and disease may become more Sequent or damaging (Steele, 1994). It should be stressed that fire behaviour and ecosystem reactions to fire vary considerably by ecosystem and attempts to link different systems should be made with great caution (Ahlgren, 1974). 3.6 Fire Types and Heat Movement in Forest Floors and Soils The three main types o f fire are: ground fires, surface fires, and crown fires (Figure 3.1). Each o f these types has different properties and characteristics and, thus, will have different effects on the forests they bum. The severity o f each of these types of fire partly may be described by the temperatures reached within the forest floor and the duration o f the heating experienced by the vegetation, in the forest floor and underlying mineral soil (Hartford and Frandsen, 1992). However, the degree to which a soil - 25- can be heated during any type of fire is dependent on the type o f fuel, fire in ten sif and duration, nature o f the litter layer and soil properties (such as the level o f organic matter, moisture content) and is, therefore, highly variable (Wells et a i, 1979). When water is present in the soil, the temperature o f the soil will not exceed 100°C until the water has evaporated or leached to lower soil layers (Wells et a i, 1979). Figure 3.2 demonstrates how temperature changes affect different selected soil constituents or properties. Figure 3.1 Schematic illustration o f ground, surface and crown lire locations CROWN FIRES } SURFACE FIRES GROUND FIRES Duff Layer Mineral Soil Ground fires (or subsurfiice fires) bum duff, roots, buried wood and peat below the litter layer o f the forest floor. They normally s iq ^ r t smouldering or glowing combustion as duff slowly is pyrolysed - 26- Figure 3.2 Effects o f temperature on selected soil constitaents. •c ' 750 900 maximum surface temperature in pine needle fires, Ontario (8) 725 700 716-------maximum temperature at surface of chaparral fire, California (9) 700____ temperature exceeded at mineral soil surface in high intensity fire (3) 675 ^^6 5 0 625 600 600 maximum surface temperature in a jack pine fire (6) 575 IM 550 525 500 500_____ removal of hydroxyl ions adsorbed on montmoril Ionite, illite and kaolin cl^s <3cm depth in mineral soil (1) 475 450 400-500 long duration causes ashing o f organics (4) 425 400 375 """3 5 0 325 300 275 " 250 225 200 175 H 150 125 100 75 ^ ^ 5 0 370..........many hydrophobic materials completely vapourized after 15 minutes (I) 300-390 rapid pyrolysis occurs (4) 300.........up to 60% of a site's N can be volatilized 275____ maximum temperature achieved 2.5cm below surface o f an extreme eucalyptus forest, Australia (9) 260..........maximum duff temperature below ponderosa pine/incense cedar fire (9) 250____ soil humus destroyed (3) 245_____maximum surface temperature below ponderosa pine/incense cedar fire (9) 240 —organic material pyrolyzed (7) 210____ lethal temperature for bacteria in dry forest soil (9) 200.........removal of water adsorbed on montmorillonite, illite and kaolin clays <3cm depth in mineral soil (1) 200..........maximum temperature achieved 2.5cm below intense chaparral fire, California (9) 200 .N loss from ponderosa pine forest (9) 200.........some soil microorganisms can still survive (7) 175.........soil water repellency intensified (1) 155____ lethal temperature for fimgi in dry soil (1) 150.........grass seetk can survive for 5 minutes (4) 140____ Nitrosomonas can be killed in a dry soil (9) 110......... lethal temperature for bacteria in wet forest soil (9) 100.........soil temperatures not exceeded if moisture present (9) 100.........most microorganisms die (4) 100.........lethal temperature for fungi in wet soil (1) ICO.........Nitrobacter can be killed in dry soil ( 1) 94...........near total loss of VAM colonization (5) 75...........Nitrosomonas can be killed in wet soil (9) 50-60......plant tissue death (4, 7) 50...........Nitrobacter can be killed in wet soil (9) 25 (1) Agee, 1993, (2) Andison, 1994, (3) Groeschl et al.. 1990, (4) Hartford and Frandsen, 1992, (5) Klopatek et al.. 1988, (6) Maclean et al.. 1983, (7) Steward et al.. 1989, (8) Van Wagner, 1972, (9) Wells et al.. 1979. - 27 - to char (Hartford and Frandsen, 1992; Merrill and Alexander, 1987). However, moisture and the presence o f inorganics can stop the smouldering combustion and extinguish ground fires (Hartford and Frandsen, 1992). Sandberg (1980) showed that duff with a moisture content greater than 120% wül not bum regardless o f the amount o f surface fuels, while Hawkes (1993) found that peat material would smoulder in conditions o f over 200% moisture content when an external heat source (like that fiwm a surface fire) was applied. Surface fires are fires in Wiich the materials above the duff layer act as the fuel source o f the fire (Merrill and Alexander, 1987). Crown fires occur when the standing and supported forest materials which are not in direct contact with the groimd (foliage, twigs, branches, cones) are the primary fuel source for burning (Merrill and Alexander, 1987). Both crown and surface fires bum by fla m in g combustion as pyroiysing fuel releases volatile gases that mix with air and are heated to ignition (Hartford and Frandsen, 1992). All three fire types can occur in one forest fire and are usually not separate entities. The direction o f the prevalent wind in relation to the aspect o f the slope upon which a fire is burning is important in determining fire behaviour. Wind tilts flames of a fire forward which results in a preheating o f the fuels ahead o f the fire firont. The heating o f the fuels leads to increased spreading rates o f the fire and increased fire intensity. The slope reacts in much the same manner by tilting fuels toward or away fi-om the flaming fixjnt (McAlpine et a i, 1991). Generally the fine fuels (s 7 cm in diameter) are the first to ignite during a fire. They may act as kindling to the large fuels (> 7 cm in diameter) and combust quickly because o f their low moisture content and high surface-to-volume ratio (Little, 1990). Moist duff can provide considerable protection fi-om heating to the mineral soils below (Hartford and Frandsen, 1992). The presence of water in duff, - 28 - or within the mineral soil itself, changes the heat capacity and thermal conductivity o f the substrate (Frandsen and Ryan, 1986). Since water absorbs 4.18 joules for each degree Celsius increase in temperature, following evaporation, less energy remains for heat transfer than would be experienced in dry duff or a dry mineral soil (Agee, 1993). In addition, moisture within the duff layer can act as a prevention to ignition o f ground fires (Hungerford et a i, 1993). However, while moisture will decrease the maximum temperature o f the heat being transferred, the wet soil is still a better conductor o f the remaining heat and may transfer it to greater depths than might be experienced in dry soils (Agee, 1993). Hungerford et al. (1993) predicted that moisture levels in duff adjacent to a burning zone may affect the progression o f the fire. It is possible for moisture to be drawn in to replace moisture lost by the advance o f the fire as well as the possibility for moisture to be pushed away fi-om the burning zone. However, the condition o f these fijels depends, in part, on the weather. Dead fiiels will reflect moisture regimes o f both past and recent weather, whereas live fuels will reflect a more seasonal regime (Rowe and Scotter, 1973). The materials composing the duff layer acts as a factor in determining how deep a fire will bum in this layer. In their examination o f duff consumption models, Reinhardt et a/. (1991) determined that, under specific conditions, duff derived o f short needled litter were more readily consumed than duff firom longer needled forests. Figure 3.3 provides a generalized g r^ h o f the relationships between fire duration, fuel moisture content and the percent o f the fiiel consumed. O f note are the times following fire initiation and the moisture content versus the type o f fuel. The fine fuels (< 7 cm in diameter) are the first to ignite and then the heat generated firom their flaming acts as kindling for the remainder o f the fuels. In their study within the moist, cool SBS subzone in central British Columbia, Taylor et al. - 29 - Figure 3 J Relationship between fire duration and moisture content to the amount of resources consumed. Fine fucb 100 Large fncb Forest floor Live shrubs Large, rotten logs Short Wet Fire Duration Long Moisture Content Dry Note; fine fiiels £ 7 cm diameter, large fuels > 7 cm diameter. from Little, 1990 (1991) indicated that the observed depth and duration o f 60°C temperatures were related to plant tissue death (also see Hartford and Frandsen, 1992; Steward et a l, 1989) and were linked with the amount o f slash and forest floor consumed during a fire event Their study showed that the maximum temperatures reached in the spray and bum and the broadcast bum treatments were sufficient to kill above-ground plants in most o f their locations and below-ground plants in 20% o f their locations to a depth o f 3 cm and 3% to a depth o f 7 cm. W ithin the same biogeoclimatic zone, Blackwell et a i (1992) determined that consumed biomass from a fire increased with prebum biomass levels regardless o f the moisture content o f the fuel because the slash had been placed in windrows for burning. - 30- 3.7 Fire Patterns within the McGregor Model Forest Over the forty year period from 1951 to 1991, the B.C. Ministry o f Forests, Protection Branch recorded 403 fires occurring within and immediately surrounding the McGregor Model Forest in Central British Columbia (Taylor, 1995). These fires burned almost 2000 ha within four different biogeoclimatic zones and six subzones. Table 3.3 shows the numbers o f fires per subzone and the total area burned. Table 3.3 BGC Zone SBSvk SBSwk SBSmk ESSFw k IC H vk Tundra Unclass Total from Taylor, 1995 Fires within the McGregor Model Forest between 19S1 and 1991 according to # o f fires % o f fires 150 197 19 20 12 4 1 403 37.2 48.9 4.72 4.96 2.98 0.99 0.25 100 T otal (ha) 974.3 979.5 19.9 4.6 2.1 0.2 0.1 1980.7 % o f total burned area 49.2 49.5 1.00 0.23 0.11 0.01 0.01 100 (vk = very wet, cool subzone; wk = wet, cool subzone; mk = moist, cool subzone; ESSF = Engelmaim Spruce-Subalpine Fire zone; ICH = Interior Cedar Hemlock zone) O f the 366 fires recorded within the SBS biogeoclimatic zone o f the McGregor Model Forest between 1951 and 1991, only 13 fires burned areas greater than 10 ha, yet these fires represented more than 97% o f the total area burned (Taylor, 1995). Figure 3.4 shows the locations o f all the fires within the McGregor Model Forest which were greater than 10 ha. Six major causes o f forest fires occurring within the McGregor Model Forest have been recognized by the BC Ministry o f Forests, Protection Branch: (1) lightning; (2) recreational activities; (3) railroad activities; (4) logging activities; (5) other industrial activities, and; (6) land clearing and brush - 31- Figure 3.4 1951-1991 fires greater than 10 h« within the McGregor Model Forest Size of Area Burned « >10 ha k >50 ha >100 ha k H 54-22.5" 54-18.75"- - f - >500 ha 5 4-5" — 1 » 10 ton L 54-7.5" -jfC . I- 54:00" from Taylor, 1995 burning (B. Hawkes, personal communication, 19%; Taylor, 1995). Table 3.2 provides a breakdown o f the listed causes o f the fires recorded within the McGregor Model Forest. Again, the dominance o f lightning-caused fires is demonstrated as they are responsible for over 93% o f the total number of fires accounting for almost 69% o f the total burned area. 3.7.1 The SBS Subzones within the McGregor Model Forest Over 90% o f the fires within the McGregor Model Forest were within the SBS biogeoclimatic zone (the largest zone within the McGregor Model Forest) encompassing over 99% o f the total area - 32 - Table 3.4 Causes o f fires within the McGregor Model Forest between IS>51 and 1991. # o f fires % of fires Total Om) % of total area burned Lightning 376 93.30 1358.6 68.6 Recreation 2 0.50 0.2 0.01 Railroads 2 0.50 3.6 0.18 Logging 16 3.97 533.6 26.9 Other industrial 1 0.25 81.6 4.12 Land clearing brush burning 1 0.25 0.1 0.005 Unknown 5 1.24 3 0.15 Total 403 100 1980.7 100 Cause of fire from Taylor 1995 burned. O f the remaining subzones, only the ESSF and ICH account for more than 0.1% o f the total burned area. The tundra and one unclassified zone combine for only five fires burning an area o f less than 0.02 ha and will not be discussed further. Surface and crown fires predominate the SBS with mean fire return intervals between 100 - 150 years on average burning 50 - 500 ha (Parminter, 1992). Tables 3.5,3.6 and 3.7 detail the breakdown of the fire record for the different SBS subzones within the MME. O f particular interest are the contrast between the high fiequency o f fires burning small areas compared to the few very large fires. In each case, the number o f fires over 5 ha account for less than five percent o f the total number o f fires in the subzone while accounting for the majority o f the area burned. This may be considered an indication of the fire history o f this area with many small fires being highlighted by very few stand replacing fires. However, it should be noted that the fires recorded belong to a period o f fire siqipression and may not be - 33 - representative o f fire prehistory within the area. This trend is also prevalent in each o f the other biogeoclimatic zones occurring within the McGregor Model Forest. Table 3.5 Fires in the SBSvk bios eoclimatic suhzone within the McGrejgor Model Forest. Size (ha) 0 0.1 0.2 0.3 0.6 0.6 0.8 1 1.8 3.5 4 10.6 10.9 22 35 68 161 642.1 Total # o f fires % o f fires 20 109 6 1 1 1 1 1 1 1 1 1 1 1 1 I 1 I 150 13.33 72.67 4.00 0.67 0.67 0.67 0.67 0.67 0.67 0.67 0.67 0.67 0.67 0.67 0.67 0.67 0.67 0.67 100 from Taylor, 1995 - 34- Total (ha) % of total burned area 0.00 0 1.12 10.9 0.12 1.2 0.03 0.3 0.6 0.06 0.06 0.6 0.08 0.8 0.10 1 0.18 1.8 0.36 3.5 0.41 4 1.09 10.6 1.12 10.9 2.26 22 3.59 35 6.98 68 16.52 161 65.90 642.1 100 974.3 Table 3.6 Fires in the SBSwk biojEeoclimatic subzone within the McGregor Model Forest. # o f fires S ize^ a) Vo of fires Total (hn) Vo o f total burned area 24 0 12.18 0 0.00 0.1 132 67.01 132 1.35 11 0.2 5.58 2.2 0.22 0.3 3 1.52 0.9 0.09 0.4 2 1.02 0.8 0.08 1 0.51 0.5 0.5 0.05 1 0.51 0.7 0.7 0.07 1 0.8 0.51 0.8 0.08 1 1.02 2 0.20 1 1.2 1.2 0.51 0.12 1 0.51 1.5 0.15 1.5 1.7 1 0.51 0.17 1.7 1.52 6 0.61 2 4 0.41 1 0.51 4 1 0.51 4.1 0.42 4.1 4.8 0.49 1 0.51 4.8 5.2 0.53 1 0.51 5.2 5.6 0.57 1 0.51 5.6 0.61 6 1 0.51 6 13.3 1.36 1 0.51 13.3 1.64 16.1 0.51 1 16.1 16.9 1.73 0.51 1 16.9 1.98 19.4 0.51 1 19.4 58 5.92 0.51 1 58 8.33 81.6 0.51 1 81.6 32.87 322 0.51 I 322 39.92 391 0.51 1 391 100.00 979.5 100 197 Total from Taylor, 1995 - 35- Table 3.7 Fires in the SBSmk biogeoclimatk subzonc within the McGregor Model Forest. Size (ha) # o f fires % of fires % of total burned Total Ow) area 0 0.1 0.2 0.8 6.2 11.3 Total 2 12 2 1 1 1 19 10.5 63.2 10.5 5.26 5.26 5.26 100 0 1.2 0.4 0.8 6.2 11.3 19.9 0.00 6.03 2.01 4.02 31.2 56.8 100 from Taylor, 1995 Figures 3.5, 3.6 and 3.7 show the spatial distributions o f the recorded fires within the different subzones o f the SBS. Each o f the quadrats represents an area o f approximately 5800 ha and was delineated by latitude and longitude. 3.8 Fire and Soil Nutrients Fire is the m ain force involved in nutrient recycling in the forests o f the Rocky Mountains. It pro\ades the opportunity for nutrients Wiich are immobilized in biomass and soil to be recycled into the soil through the burning o f organic matter (Lathrop, Jr., 1994; Steele, 1994). This is important as low rates o f decomposition in northern boreal spruce forests tend to tie up the nutrients in the forest floor m aking them largely unavailable to plants. However, forest fires can lead to the loss o f nutrients through vo latilization during pyrolysis or combustion, loss in the particulate matter o f smoke, transfer o f mineral elements to the ash layer, leaching and the heating of biomass and upper soil layers (sometimes to temperatures above lethal levels for microbial survival) as well as being blown away with ash residues following the fire (Feller, 1982; Grier, 1975; MacLean et a i, 1983). - 36- Figure 3.5 1951 - 1991 fires in the SBSvk w ithin and im m ediate^ surrounding the ___________ M cGregor M odel Forest.______________________________________________ #arilRspcr S tW h aiq aarc #e = SBSvk * <5 à A k < 10 <15 < 10 54*11 S 4 3 .7 f 54:00- Forest fires also lead to a redistribution o f nutrients within ecosystems. Figure 3.8 shows the direct and indirect affects o f fire on nutrient cycling in northern ecosystems. However, MacLean et a l (1983) note that the magnitudes o f the redistributions have not been well quantified; although the direction o f the movement is well understood. 3.8.1 Post-Fire N utrient Cycling Burning o f forests has been shown to increase the short-term availability o f nutrients to the soil, but also show the adverse effects o f nutrient loss over the longer term (Hawkes et a l, 1990)with variations between the different nutrients. Figure 3.9 dem onstrates the loss o f selected - 37 - Figure 3.6 1951 - 1991 fires in the SBSwk within and immediately surrounding the ___________ M cGregor M odel Forest._____________________________________________ # of Arcs per 5M0 ha iqaare =SBS#k snof ft <5 » <10 54^26^S4'22J’ - % <15 54-18.7y - kt 54-IS' - <20 '1 ^ , — S4*n^- T---sns sunns' 54-00' nutrients from the soil through volatilization as a function o f increasing temperature. The potassium and sodium, however, may be released from plant tissues leading to increased cation concentrations in the soil (Helvey et al., 1976). Feller (1989) stated that the best method to measure nutrient losses to the atmosphere from forest fires was to determine the depth-of-bum o f the forest floor. In the Coastal W estern Hemlock biogeoclimatic zone. Feller (1989) found that total nitrogen levels in the forest floor were reduced by 60-85%. Several other nutrients experienced heavy percentage losses from burning (phosphorus 30-75% , potassium 20-60%, magnesium 60-85%, and calcium 20-50%) though nitrogen losses were the greatest (by weight) ranging from as low as 10 kg/ha to as much as 1000 kg/ha in areas - 38- 1 Figure 3.7 1951 - 1991 fires in the SBSmk within and immediately surrounding the M cGregor M odel Forest._____________________________________________ # of fires per SMO hm sqoarc = SBSmk t <5 h <10 <15 k k 54-15* <20 - 10km 54*1I25’- T----- 54T3.75’ - - L — — 1— — — I — — — I I ! S4‘0(r —1—— with prebum slash loads between 10 kg/m^ and 30 kg/m- and depth-of-bums ranging from 0.1-6.4 cm. This is similar to maximum losses o f total nitrogen o f900 kg/ha from the soil in Pacific Northwest forests (Agee, 1993). Feller (1989) further recorded total nitrogen losses fiom broadcast slashbums within the SubBoreal Spruce biogeoclimatic zone o f 551 kg/ha (depth-of-bum = 3.0 cm) and 324 kg/ha (depth-of-bum = 1.9 cm) in mesic and subhygric sites, respectively. It should be noted, however, that nutrient losses from fire may be partially offset by the deposition from precipitation. Helvey et al. (1976) determined that as much as 1.1 kg/ha o f nitrogen and 8.5 kg/ha o f the four base cations (Ca, K, Mg, Na) was deposited in the annual snowfall. Their - 39- Figure 3.8 Possible direct and indirect effects o f Are on nutrient cycling in northern ___________ecosystem s.__________________________________________________________ Legend Direct fosses o f nutncccs from the ecosystem during fire. —> ecosystem nsuitiog from Are. indirect cflTects o f fire on nutrient cycling. -> .4- W Nutrient Stores in Vegetation (Pre-Fire) Mh cMvcctlna I tranifcr I*' I M irkaU I" I «vaUiMc Nutrient Stores in Vegetation (Post-Fire) Ash Layer (Post-Fire) iraixcnhatiM by wiad kacfeiataad mrCKc ■h UpH ■■Meat transfer^^ 1------------------------------------ SoU "Available" Nutrients N fiialinn iacnkcd accoaipMilkHi ud ■HunliiaiiM changes in ‘ microbial populations from MacLean et a/., 1983 - 40 - Son Organlcaily Bound Nutrients increased soil temperature and active layer depth Figure 3.9 Loss o f soil nutrients at various temperatures. 900 800 sodium inorganic phosphorus 700 600 500 potassium sulfur 400 organic phosphorus 300 200 nitrogen 100 w ater from Agee, 1993 Study in W ashington State was climatically similar to areas w ithin the interior o f British Columbia. Their watershed had an annual precipitation minimum and maximum o f 203 mm and 787 mm, respectively, w ith an armual average o f 579 mm at 915 metres above sea level (m.a.s.L); these precipitation values are within the lower ranges o f the SBS biogeoclimatic zone. One method o f determining nutrient loss from fires is to examine the levels o f nutrients in streams or channels. W ith natural background levels determined prior to a fire event, changes in the amoimts o f nutrients which normally runoff or are leached to ground water may be followed (Feller - 41 - ; and Kimmins, 1984; Helvey et a i, 1976; Lathrop, Jr., 1994). In their study, Helvey et a l (1976) followed nutrient cycling over a three year period in three Pacific Northwest watersheds following forest fires. Total nitrogen was found to rise steadily following the fire event while the base forming cations i I dropped in concentration due to increased runoff into streams (Table 3.8). However, Lathrop, Jr. (1994) noted that nutrient uptake by vegetation which begins to occur during vegetative succession in the months and years following the fire event eventually leads to a decrease in nutrient leaching into streams. Table 3.8 Nutrient changes in streams following a Pacific Northwest forest fire. N utrient 1970 (Pre-Fire) mg/L 1971 (1 YR Post-Fire) mg/L 1972 (2 YR Post-Fire) mg/L T otal N 0.047 0.064 0.10 Ca 8.8 7.3 5.0 Mg 1.5 1.3 0.9 Na 2.9 no data 2.3 K 1.3 no data 0.9 Base Cations 14.5 12.5 9.1 (Monthly Mean) from Helvey e/a/.. 1976 Grier (1975) reported losses o f a large proportion o f base cations fi-om leaching during the first snowmelt during the spring following a late August fire in the Entiat Valley o f Washington State. The study found that 35% o f the calcium, 78% o f the magnesium, 85% o f the potassium and 94% o f the sodium originally in the ash layer was leached between the May - June sampling period. It was also - 42 - noted that over 90% o f the calcium, magnesium and potassium fix>m the percolating water was held I within the first 19 cm o f the mineral soil. Conversely, in another study, Boyle (1973) noted that not all ! o f the mineralized potassium was retained in the upper 20 cm in a Wisconsin pine plantation. This was : believed to have been the result o f the low cation exchange capaci^ o f the coarse-textured soil o f the area. Helvey et al. (1985), in another study o f nutrient loss, examined levels within transported sediments (debris torrents, suspension, bedload). In the five years following a fire event in the eastern Cascade Range o f Washington, losses o f nitrogen increased between 14 and 38 times the normal loss rate (total transported nitrogen increased fix)m 0.004 kg/ha/yr to 0.16 kg/ha/yr), available phosphorus losses were 14 times higher than pre-fire levels (from 0.001 kg/ha/yr to 0.014 kg^ha/yr), losses of calcium and magnesium averaged 26 times greater, losses o f sodium were increased by 25 times and potassium jumped to losses 32 times more than the pre-fire levels (combined losses of the four base cations increased from 1.98 kg/ha/yr to 54.3 kg/ha/yr). W ithin the SBS zone, Taylor and Feller (1986) showed an immediate increase in available nitrogen, phosphorus, potassium, magnesium and calcium levels as well as a higher pH due to the ash deposition following a prescribed bum which had a relatively low depth-of-bum and slash consumption. However, after a period o f nine months, mineralizable nitrogen and pH levels were the only two factors with levels higher than the pre-fire results. The cations had all been reduced to a level lower than pre­ fire conditions. In sandy podzolic soils (as are found within the SBS zone o f the McGregor Model Forest), nutrient gain may be short lived as water-soluble cations are easily leached when humus layers are removed (Rowe and Scotter, 1973). Combustion o f the duff layer leads to a reduction o f organic matter and a release o f cations - 43 - I (Pietikainen and Fritze, 1992; Steward et al., 1989). Combustion o f the organic matter composing the I i dug" layer also leads to the release o f mineral substances in the form o f oxides which may be turned into % carbonates and hydroxides causing a decrease in the acidi^ o f the soil (Fritze et a i, 1993). Andison I I (1994) noted that it is rare for the entire layer o f organic matter to bum and that the consumption o f I \ organic matter is predicated by its moisture content and the fire intensity (specifically the residence time I and downward heat pulse firom the surface fire). The level to which a fire may affect soil nutrients has been tied to the clay and humus content of the A horizon (Kelsall et ai, 1979). It has been hypothesized that soils having a high clay content and a “substantial” humus content in the A horizon would lose a minimal percentage o f their nutrient base from burning. Conversely, soils low in clay and humus in the A horizon rely on the forest floor (L, F and H horizons) for their moisture and nutrient-holding capacity and may be subjected to more severe changes to their physical and chemical properties such as an increased bulk density, lower water-holding capacity and reduced fertihty. Following a fire in a Mediterranean-type forest in Israel, Kutiel and Naveh (1987) found an immediate flush o f ammonium and nitrate which retumed to pre-fire levels over a period o f two to four months. Total phosphorus jumped 300% immediately after the fire due to the turning o f the plants and litter into ash, but the levels retum ed to pre-fire levels within two months. It was believed that the reduction o f nutrients following the post-bum increases were primarily due to leaching from rain. Similar findings were reported by Lewis, Jr. (1974) in a South Carolina pine forest. In southem pine forests, Groeschl et a i (1990) found that low intensity fires improve the soil fertility by raising the pH and providing an influx in inorganic forms o f nutrients and increasing the solubility o f the nutrients. Low intensity fires can also volatilize monoterpenes and other similar - 44 - I compounds which inhibit bacterial growth necessary for ammonification and nitrification (Groeschl et I a/., 1990). However, high intensity fires can remove significant amounts o f the total nutrient capital j resulting in a depletion o f a site's fertility (Groeschl et ai, 1990). In the case o f high intensity southem j pine fires, volatilization and eventual runoff once the forest floor was removed led to the lower total j carbon levels. However, the translocation o f carbon may have lead to increased levels in downslope I I positions. Soil pH also was found to increase following high intensity fires (Groeschl er a/., 1990). I I 3.8.2 Post-Fire Nitrogen Levels I Fire can affect soil nitrogen levels in two main ways: directly by volatilization and oxidation of nitrogen present in soil organic matter as well as indirectly by altering soil chemical and physical properties which affect soil nitrogen transformations (Mroz et al., 1980; Wells et a i, 1979). Nitrogen is easily volatilized during combustion because it can be released fiom the organic matter in the form of | nitrogen gas or nitrogen oxides (McNabb and Cromack, Jr., 1990). Macadam (1989) noted that nitrogen may be the most limiting nutrient in British Columbia’s forests, partly because the soils are relatively “yotmg”. While more than 90% o f the nitrogen in the i forests are associated with organic materials, less than 2% o f the total content o f nitrogen is in a form usable to plants (Macadam, 1989). More than one-third o f the total nitrogen in the SBS may be found to a depth o f 30 cm fiom the forest floor making this nutrient very susceptible to volatilization during : combustion (Macadam, 1987). However, in the SBS, low soil temperature may be more limiting than low nutrient levels. The loss of nutrients fiom volatilization during the burning o f the forest floor may be outweighed by the amelioration o f the microclimate as higher soil temperatures make conditions better for plant growth. A post-fire increase in soil temperature of 10“C can provide the opportunity for - 45- conifer seedling survival (Macadam, 1987; Silversides et ai, 1986). This was confirmed by Ballard and Hawkes (1989) who studied 5 - 1 6 year-old planted white spruce in the McLeod Lake area o f the SBS north o f Prince George. They determined that spruce trees planted on burned sites would grow faster than those on unbumed sites even though they showed nitrogen deficiencies. I Studies tend to show an immediate loss o f total nitrogen contents due to volatilization II accompanied with an increase the concentrations o f available forms o f nitrogen which are mobilized from the burned woody plants, the forest floor litter, duff layer and the microbial biomass (Beese, 1992; Christensen, 1973; Curran, 1994; Feller, 1982; Kutiel and Naveh, 1987; Mroz era/., 1980; Okano, 1990; i I Wells et a i, 1979). A summary o f reported changes in nitrogen levels due to fire events are provided from selected studies in Table 3.9. Vitousek et a l (1989) suggest that, in many ecosystems, the levels o f total nitrogen may increase I or decrease naturally during late secondary succession. This would have ramifications in determining I I how much nitrogen may be mineralized during a fire. It was suggested that the severity o f the climate would be a regulator in determining the naturally occurring background changes in mineralizable nitrogen during serai stage. Pyles et a i (1991a) determined annual nitrogen mineralization rates in a forest within the Coastal Western Hemlock biogeoclimatic zone on Vancouver Island to range from 20 to 60 kg/ha/yr two years following prescribed fires. These levels were expected to support plantation growth provided the areas were not treated with a severe prescribed bum (high depth-of-bum) or occurred on coarse-textured soils. The soil was described as well-drained Humo-Ferric Podzols developed on loamy glacial till or colluvium which are also common in the SBS zone (Coupé et a i, 1991 ; Meidinger et ai, 1991). - 46 - Table 3.9 Chan ge in nitrogen levels following fire events. Ecosystem/Locatkm TiBM Period Change Form of Nttroeen Reference Coastal BC - immediately post-fire Total N California chaparral - immediately post-fire Total N - first rainfall post-fire C6 mm rain) - subsequent rainfall - 30 years post-fire (slash and bum) NOj-N 1 10% (216 kg/ha) for lowest impact bum : 81% (1328 kg/ha) for highest impact bum 1 61-88% represented in loss o f forest floor - decrease to 2.7 mg/g fi-om 3.0 mg/g soil - 40-50 pg/ml leached NO,--N forest floor N -none - retumed to within 0.5% of pre-fire levels Curran, 1994 forest floor N 197% Grier, 1975 A horizon Total N Total N 133% Total N NH/-N NH/-N NOj-N - retum to pre-fire levels - 2X pre-fire levels r 76.6% T36.8% Total N available N I 10.4% - increase from 0.93% to 1.55% - retumed to pre-fire levels Cowichan Lake, BC Entiat Valley/ Washington - immediately post-fire Aleppo pine/lsrael - immediately post-fire Red Pine/Michigan - 3 months post-fire - 8 months post-fire - 3 days post-fire Eastern Hemlock/ Michigan Douglas-fir-westem larch/Montana - 5 weeks post-fire available N - 3 days post-fire NH/-N NO,--N Total N available N - 5 weeks post-fire available N - 3 days post-fire NH/-N NOf-N Total N available N - 5 weeks post-fire available N - 47 - I 25% T2.2% T49.6% 1 8.5% - increase from 0.71% to 0.93% - retumed to pre-fire levels I 172% I 242% I 32% - decrease fix)m 1.04% to 1.03% - retumed to pre-fire levels Beese, 1992 Christensen, 1973 Kutiel and Naveh, 1987 M roz e t al., 1980 (laboratory analysis) Sub-Boreal Spruce/ B.C. - immediately post-fire (slash-burning) Total N Western Oregon - immediately post-fire NGj-N Ponderosa pine Loblolly pine Douglas-fir/ Washington Conifer forest/ Washington chaparral - immediately post-fire - immediately post-fire - immediately post-fire fi-om slash-burning - immediately post-fire Total N Total N Total N I 44% (470 kg/ha) firom mesic, low impact site 1 46% (650 kg/ba) fi-om mesic, moderate impact site I 4% (156 kg/ha) fi-om subhygric/hygric, low impact site I ^/o (358 kg/ha) fi-om subhygric/hygric, moderate impact site - losses of 0.92 kg/ha following broadcast burning following clearcut compared to 0.05 kg/ha on undisturbed forest - loss of 140 kg/ha - loss o f 112 kg/ba - loss o f750 kg/ha Total N - loss o f907 kg/ha Pine (species not specified for laboratory study) Tobosagrass/Texas Fir (species unspecified) - immediately following prescribed bum - immediately post-fire Total N I 10% NH/-N - increase o f 24 kg/ha - 5 years post-fire litter-N - 7 years post-fire Total N - returned to pre-fire levels - retumed to pre-fire levels due to Nfixation Taylor and Feller, 1986 Wells et at., 1979 Note: 1 = loss, i = increase compared to pre-fire levels. Feller and Kimmins (1984) have noted that natural nitrogen replacement in southwestern British Columbia occurs at levels o f 4 kg/ha/yr through precipitation and less than 0.1 kg/ha/yr from mineral weathering. It remains unclear as to whether these rates are sufficient to replace all the nitrogen lost from a slash-burned area if an 80-year stand rotation is expected. - 48 - Fyles et al. (1991a) felt a considération o f the spatial pattern o f mineralizable nitrogen following forest fires was required. Stand development reacts less favourably in areas where mineralizable nitrogen has accumulated in a thick humus layer encompassing small areas compared to sites where a thin humus layer has a more homogenous pattern. In the most severely burned area o f their study, 50% o f the mineralizable nitrogen encompassed only 5% o f the burned area. Studies have shown that biomass and nitrogen levels in Pacific Northwest forests tend to increase in all above-ground components o f young forests with the relative distribution between crown and stem remaining somewhat similar. The colder and moister the system, the longer the period o f time in which the biomass will have to accumulate and trap nitrogen. Release o f the vital nitrogen requires cycling by soil organisms, precipitation or oxidation by fire (McNabb and Cromack, Jr., 1990). In their study o f the Douglas-fir/westem larch forest, Mroz et al. (1980) found that ammonium and nitrate in the litter can be assimilated by increased microbial activi^ within three days o f the fire event. However, the opposite was found in red pine (Pinus resinosd) and eastern hemlock (Tsuga canadensis) samples. As such, Mroz et al. (1980) concluded that generalizations o f the effects o f fire on soil nitrogen over large areas having different forest floor materials would be invalid. An example they presented was the much larger amount of nitrogen found in the litter o f a Douglas fir/westem larch forest as compared to a hemlock or red pine forest. In their research o f prescribed burning in ponderosa pine forests wbich are dominated by surface fire regimes, Ryan and Covington (1986, in Steele, 1994) discovered levels o f ammonium that were as much as 80 times higher than similar unbumed stands. Levels o f total carbon and nitrogen following southem pine forest fires were found to react differently according to the intensity o f the fire (Groeschl et al. 1990). They found that low intensity - 49 - bums caused total carbon and nitrogen to increase in the upper mineral soil layers fiom the pre-fire levels. The increase in total carbon was due to the redistribution and leaching o f colloidal-sized charred material firom the residual ash by gravity and water. Increases in total nitrogen were believed to have been correlated to increased carbon levels during Ng-fixation. Stevenson (1986, in Groeschl et a i, 1990) found that Nj-fixation could account for as much as 100 kg/ha/yr. Other studies in different types of ecosystems showed similar results (i.e. Christensen, 1973 in California ch^xarral; Viro, 1974 in Finland; as well as others mentioned in Mroz et a i, 1980; and in Wells et ai, 1979). While increases in nitrate levels have been found following forest fires, Christensen (1973) noted that nitrate levels before and after fires in the California chaparral system were “nearly equal” and the. study of Kutiel and Naveh (1987) in an Aleppo pine system in Israel indicated that the nitrate increases were the result o f greater mineralization rates following the fire and not due to the burning. It should be cautioned that these results are fi^om Mediterranean ecosystems and may not be transferrable to temperate systems. The work o f Penn et a i (1993) has shown that post-fire ammonium concentrations in soils were found to be significantly higher over the initial two-year period following the bum, then declined. It was also shown that total nitrogen and mineralizable nitrogen increased with stand age up to 50-60 years in a Mediterranean chaparral ecosystem, then decreased. However, ammonium concentrations increased for only the first two years following the fire, after which they retumed to pre-fire levels. They also noted the different effects o f different tree species on the levels o f nitrogen in the soil. In their study in an Aleppo pine forest in Israel, Kutiel and Naveh (1987) found that total nitrogen dropped by 25% immediately following a fire. However, they also discovered that the total nitrogen had retumed to its pre-fire levels within a few months o f the bum. - 50 - It should be noted that some studies have shown that total nitrogen has not always been found to increase in underlying soil layers following forest foes (see Isaac and Hopkins, 1937 in Mroz et al, 1980). 3.9 Summary o f Soil/Fire Interactions Many parameters afifect how an ecosystem will react following a fire. Fire regime, depth-of- bum, site geography (aspect, slope, hydrology), types o f forests, types o f available foels and foel loading and consumption, vegetation and climate all must be considered when examining fire effects. Furthermore, when studying forest fires, researchers and forest managers must take into account the. spatial context of historic fire patterns: fires traditionally did not operate solely on a stand-by-stand basis though that is reflected in m any current stand management practices (Mutch, 1994). While subalpine and boreal ecosystems in Canada are not expected to maintain specific species compositions for periods o f over 500 years (Johnson et a l, 1995), current fire suppression practices are attempting (indirectly) to make this happen by not viewing these forests as dynamic systems. Forest harvesting is supplementing the cycling by fire in many o f these ecosystems. Examination o f the fire record for the McGregor Model Forest firom 1951 to 1991 indicates a pattem of small (less than 0.1 ha) fires occurring over the entire landscape. A few large fires, however, were found to dominate fire-caused changes in the landscape. Different ecosystems, and indeed different areas within ecosystems, react differently to fire with respect to nitrogen transformations. An immediate loss in total nitrogen has been found by many studies to coincide with immediate increases in available nitrogen, particularly nitrate. Whether a decrease in total nitrogen will affect the long term soil and tree productivity will depend on site characteristics such - 51- as nutrient and moisture status. In Lindeburgh’s (1990) review o f the effects o f prescribed fire on site productivity, two main conclusions were made; (1) less severe fires showed less o f a risk o f causing site degradation than fires o f higher severity, and; (2) drier, nutrient-poor sites were more likely to be degraded than moister, nutrient-rich sites. - 52- Chapter Four - MATERIALS AND METHODS 4.1 Soils of the McGregor Model Forest: ARC/INFO Database Preparation The database was created in ARC/INFO, a GIS which is commonly used by British Columbia's government agencies and the corporate sector. The project was prepared in a UNIX based Silicon Graphics Incorporated format. The polygon structure was digitized fiom soils and surficial geology maps which were prepared by the Ministries o f Agriculture, Forestry and the Environment in the 1960s and 1970s. Four soil survey reports (B.C. Soil Survey Reports 2 ,4 , 10,23) and six surficial geology and landform maps which had been superimposed upon Canadian National Topographic System maps (93-1/3, 93-1/4,93-J/l, 93-J/2, 93-J/7, 93-J/8) were used (Dawson, 1989; Farstad and Liard, 1954; Hortie et ai, 1970; Kelly and Farstad, 1946). All soil mapping which led to the soil sur\ey reports were completed at the reconnaissance level through the use o f aerial photographs and, therefore, meant for use in overview management decision making rather than site level diagnostics (Dawson, 1989). Original mapping was conducted on 1:100,000 scale National Topographic Series maps having been based on aerial photographs. The attribute information (including soils series, general topography, parent material texture and drainage information) included in the INFO file was developed fiom these maps as well as fiom soil survey reports. A spatial query was formulated to obtain the total number o f polygons and the area they represented o f the soil associations representing the study sites within the McGregor Model Forest. This information was to be used for the nitrogen projections. - 53- 4.2 Site Selection The sites were chosen as part o f an investigation into the ecological processes operating within the McGregor Model Forest Each site (1) was part o f the same biogeoclimatic subzone (SBSvkl) in order to minimize variations in precipitation, temperature and vegetation; (2) had mesic/subhygric moisture regimes in order to minimize hydrologie variations; (3) showed no evidence of prior tree cutting due to harvesting or thinning operations, and; (4) was at least 20 m - 30 m fiom obvious clearings, stands o f other ages or stands not meeting the aforementioned criteria. The sample area at each site was defined by a 30 m x 30 m quadrat (Delong et al., 1994). While it was the intention o f this study to select all sites from within the MMF, this was not possible due to the difficulty in locating recently burned (which had not been salvage logged) and old growth post-fire sites. Therefore, to satisfy statistical requirements for the nitrogen analyses, three additional sites were selected outside the MMF. Also, two additional pedons were investigated at Site 11 in order to examine variations in soil properties on a catena formed on a relict avalanche. A Scoutmaster II GPS (global positioning system) was used to record the latitude and longitude o f each site. Figure 2.1 shows the locations o f the 10 pedons within the MMF, the four pedons described in the Table River area about 25 km north o f the MMF and the one described in the Gleason Creek area 10 km to the east o f Pass Lake. 4.3 Sample Collection and Preparation Pedons measured at least 1 m in width and were dug to depths revealing at least the top 25 cm o f the C horizons (Agriculture Canada Expert Committee on Soil Survey, 1987). Field profile descriptions were completed for both the mineral and forest floor horizons (Expert Committee on Soil - 54- Survey, 1983; Green et al., 1993). Soil samples were collected from each o f the horizons revealed within the pedon and refrigerated at 4°C prior to drying. Once air dried, the samples were passed through a 2000 ,um (10 mesh) sieve to remove coarse fragments and were then stored in sealed Mason jars until required for each o f the analyses. Four composite samples were collected from the A and B horizons for the nitrogen analyses. These were composed o f a mixture o f soil from eight points within the quadrat The points were located at one-third and two-thirds the distance between each of the four comers o f the study quadrat. These samples were refrigerated until air drying was possible. Three forest floor samples were collected from each o f the sites for use in the nitrogen analyses. Each sample was refiigerated at 4°C then air dried for analysis. Where possible, roots and non­ decomposed woody materials were removed from these samples. L, F and H horizons were separated prior to the analyses and ground to pass through a 425 ^m (40 mesh) sieve. Where boundaries between forest floor horizons were not easily discernible, or there were insufficient amounts o f horizons for analysis, horizon samples were combined and designated as the lower horizon. 4.4 Soil T em perature Mean annual soil temperature was calculated from climate data prepared for the McGregor Model Forest (Murphy, 1995). In each case, the diabatic lapse rate was represented by a decrease in temperature o f 0.6°C per 100 metre change in elevation from the base level (mean armual temperature = 2.5°C at 610 m.a.s.1.) obtained for the McGregor climate site (Murphy, 1995). A value o f 1“ C was then added to the mean armual air temperature to obtain the mean armual soil temperature (Soil Survey Staff, 1994). - 55- 4.5 SoU Characterization 4.5.1 Particle Size Analysis Fifty grams of soil sample was immersed in 200 ml o f deionized water (dH ,0) and subjected to an ultrasonic probe (set at 100 MHz) for six minutes to ensure the proper dispersion o f the soil particles. This dispersed solution was then brought to a volume o f 1000 ml with deionized water and thoroughly stirred. After seven hours, 20 ml o f solution was removed at a depth o f 10 cm by pipette and allowed to dry to determine the amount o f the clay haction. The remaining solution, and settled particles, were wet sieved with a 53 ^jxa sieve to separate the sand 6 om the silt and the remaining clay fiactions. The sand fraction remaining in the sieve was dried and weighed. The percentage o f silt in the sample was determined by subtracting the clay and sand values from the initial 50 g sample (Kalra and Maynard, 1991). 4.5.2 pH pH was measured in a 2:1 ratio o f 0.0IM calcium chloride (CaClj^HjO) to soil as well as a 2:1 ratio o f dH ,0 to soil using a Fisher ACCUMET pH Meter Model 600. In each case, 10 g of soil was used (Hendershot et al., 1993). 4.5.3 Exchangeable Cations and Cation Exchange Capacity Concentrations o f exchangeable cations (Al, Ca, Fe, K, Mg, Mn, Na) were determined for the m ineral soil horizon samples using modifications o f the ammonium acetate (NH^OAc) method described by Hendershot et a l (1993). Twenty ml l#N H ,O A c pH 7.0 was added to 5 g soil sample and further extractants were reduced by 50% throughout the procedure due to the low requirements o f the - 56- Leeman Labs PS Series ICP Spectrometer PSIOOOUV. The Cation Exchange C^)acity (CEC) was determined 6 om 25 g o f soil using the method described by BCahra and Maynard (1991) in v^iiich the exchange sites were saturated by unbufiered ammonium chloride (NH4CI). The total adsorbed ammonium (NHt") was leached by NaCl and the level o f ammonium in the leachate was determined by autoanalyser and was regarded as an estimate o f the cation exchange capacity. 4.5.4 Extractable Fe and Al Levels o f extractable Fe and Al 60m the soil mineral horizon samples were determined by sodium pyrophosphate (O.lMNa^PzO? 10H,O) and ammonium oxalate (02A/(NH,)^ Ç, Q,) extractions. The optical density o f the ammonium oxalate extracts also was measured. Sodium pyrophosphate extraction followed the procedure described by Kalra and Maynard (1991) in which the soil samples and extracting solution are combined in centrifuge tubes, shaken for 16 hours and centrifuged for 10 minutes at 13,000 rpm prior to analysis for Fe and Al using the Leeman Labs PS Series ICP Spectrometer PSIOOOUV. Modifications included the use o f 1 g o f soil and 40 ml extracting solution. Ammonium oxalate extraction of Fe and Al followed the procedure set out by the USDA (Soil Conservation Service, 1972). One gram o f soil was combined with 40 ml extracting solution (0.2M oxalic acid at pH 3.0) in a centrifuge tube, shaken for 4 hours and centrifiiged for 10 minutes at 13,000 rpm. The supernatant was then analysed for Fe and Al using the Leeman Labs PS Series ICP Spectrometer PSIOOOUV. The Optical Density o f Oxalate Extract (ODOE) was determined using extracts obtained in the - 57 - ammonium oxalate procedure following the methods o f Daly (1982). The optical density o f the extracts were recorded as absorbance at a wavelength o f 350 nm using the Perkin Elmer UVATS Spectrometer Lambda 28. 4.6 Soil Classification Fifteen pedons were classified using both the Canadian System o f Soil Classification (Agriculture Canada Expert Committee on Soil Survey, 1987) and the USDA Soil Taxonomy (Soil Survey Staff, 1994). The diagnostic horizons and other soil characteristics for each pedon were determined based on profile descriptions fi^om field examinations as well as physical and chemical data obtained in the laboratory. Following the keys to soil classification, each o f the pedons was classified into soil orders, soil great groups and subgroups in the Canadian System and from the soil orders through the suborders and great groups to the subgroups in the USDA Soil Taxonomy. 4.7 Nitrogen Analyses Levels o f soil nitrogen (total N, C/N ratio, available N Q ', mineralizable N) were determined for the A and B horizon composite samples and the forest floor samples; 54 A horizon, 54 B horizon and 80 forest floor samples were analysed. 4.7.1 Total N and C/N Ratio Total nitrogen and total carbon analyses were conducted on a Carlo Erba NA1500 Elemental Analyser using elemental standard Atropine (Fisons Instruments, 1994). This autoanalyser used flash combustion at 1020°C in an enriched oxygen atmosphere to ensure complete oxidization o f the samples. - 58 - The samples then were passed through two filters prior to passing through a chromatographic column which measured the thermal conductivity o f the gas providing an electrical charge which had been calibrated to the levels o f the two components being studied. We used 30-60 mg mineral soil samples (which had been passed through a 150 ,um (100 mesh) sieve to ensure uniformity o f sample) and 5-10 mg forest floor samples. The method has a detection limit o f 0.01% for total nitrogen and carbon. Values for one sample firom the A horizon was below the detection limit and was reported as one-half o f the detection limit. 4.7.2 Available N O / and N H / Available N O / and were determined to estimate the available nitrogen in the mineral soil and forest floor samples. Extraction o f N O / and NH,"^ was conducted using air-dried samples following the 2.0M KCl method described by Maynard and Kalra (1993). Determination o f available N levels were conducted using the autoanalyzer. Values of available N O / which were below detection limits were reported as 0.005 ppm, one-half the detection limit of the autoanalyser. 4.7.3 Mineralizable N Mineralizable N levels were determined using the procedure suggested by Powers (1980). Five grams o f mineral soil sample (1 g forest floor sample) was measured and placed into test tubes to which 12.5 ml ÆI2O was added. The sample was shaken, stoppered and incubated anaerobically for two weeks at 30°C. The sample was poured into a distillation flask, rinsed with 12.5 ml 0.4AKC1 and 0.25 g MgO and allowed to boil until 25 ml o f N H / distillate had been trapped in 5 ml o f boric acid indicator solution (as described by Bremner and Mulvaney, 1982). Titration was conducted using O.OlAf HCl. - 59- 4.7.4 Projection of Nitrogen Concentrations ARC/INFO was used to create a coverage reflecting potential nitrogen values based on the soil series, forest age classes and biogeoclimatic subzone o f the study areas. Three existing McGregor Model Forest coverages were used in this process. The first coverage was firom the soils database discussed in section 4.1 which selected the primary and secondary soil series representing each of the study areas: “AVERIL” and "DOMINION''; “DOMINION” and "AVERIL "; "BPRIDGE " and “CAPTCREEK". The second coverage included forest age classes: “<20 years " was used to represent the Early Serai age class; “40-80 years "was used to represent the Mid-Seral age class; “>141 years ' w as. used to represent the Late Serai age class. The third coverage was the SBSvk biogeoclimatic subzone. Once the new coverage was created, the areas o f each o f the nine selected regions and their percentage area covered o f the McGregor Model Forest were determined in ARCPLOT. The ranges o f nitrogen (total N, mineralizable N, available NH," and NO3, C/N Ratio) values for each o f the selected regions within the new coverage were determined fi-om the various nitrogen analyses. Finally, a map is produced firom the created coverage depicting the determined nitrogen projections. 4.8 Statistical Analyses Nitrogen levels were compared between forest stands less than 14 years (Early Serai sites 5, 6, 9, 13) following a fire event, stands between 53 and 80 years (M id-Seral sites 1 , 3 , 7 , 10, 11) following a fire event and stands which have not experienced a fire event for more than 140 years (Late Serai sites 2, 4, 8, 12). Since the region experiences cycles o f disturbance, the sites which were aged over 140 years were considered to have reached a state comparable to pre-fire levels. - 60 - Since the samples did not prove to be normally distributed, the One-W ay ANOVA statistical test was not a valid tool in this analysis (Griffith and Amrhein, 1991). As such, the non-parametric Kruskai-W allis H Test was used to exam ine the variation between the nitrogen levels o f the different age classes separately for each o f the forest floor and m ineral horizons. Tests were conducted independently for each horizon and for each type o f nitrogen (total, available and mineralizable nitrogen). A 95% confidence interval was used in all tests. The results o f the Kruskal-W alhs H-Tests should give an indication o f the levels o f change experienced by the different horizons for each age class. Significant differences in the ranked data o f available nitrogen would indicate that the ecosystem had not yet achieved a state o f equilibrium following th e . previous forest & e. In cases where significant différences were determ ined by Kruskal-W allis analysis, Fisher’s Least Significant Difference (LSD) test was conducted as a p o st hoc investigation to determine which o f the age classes were dissim ilar. A general linear model (GLM) was formulated using MINITAB® which approximated a two-way analysis o f variance examining the interaction between age and horizon on the ranked levels o f the different forms o f nitrogen. The two-way analysis o f variance fimction was not usable with the laboratory results as the data were not norm ally distributed (G riffith and Amrhein, 1991). This model grouped the means o f the ranked data in tabular form follow ing a structure similar to that o f (and providing results approaching those of) the two-way analysis o f variance. Two hypotheses were examined for each o f the five forms o f nitrogen (total N, mineralizable N, available N H / and NO; , C/N Ratio) examined in this section. The first examined the differences between the age classes and the second looked for interactions between the age classes and the soil horizons. The degrees o f freedom and critical F values were determined from - 61 - tables provided by G riffith and Amrhein (1991). As w ith the Kruskal-W allis H-Test used above, clustering o f the ranks was examined. The primary purpose o f this part o f the statistical analysis was to look for interactions between the age and horizon effects. - 62 - Chapter 5 - RESULTS AND DISCUSSION 5.1 ARC/INFO Database The ARC/INFO database contains 1024 polygons, 288 o f which contain soil information; the remainder represent mostly small w ater bodies. Soil associations, topography, soil texture, parent material texture and drainage data are included in the INFO files. M ost o f the polygons contain varying percentages o f more than one soil association. This reflects the heterogenous nature o f soils in the model forest. Available information on the study sites is presented in Table 2.1 and information on all the soil associations located within the M cGregor Model Forest (MMF) is in Table 3.2. Table 5.1 provides spatial details of the dominant associations o f these sites. The Barton soil association and the Dezaiko 2 + Captain Creek 2 complex do not occur within the MMF and have not been described. Table 5.1 Spatial query o f the ARC/INFO database o f the dominant soil associations in Soil Associations Number of Polygons Approximate Area Represented (ha> Fraction o f Total Area (% ) Averil 1 + Dominion 2 25 17000 9.0 Bearpaw Ridge + Captain Creek 7 6400 3.5 Dominion 2 + Averil 1 35 33000 18 Torpy River 2 + Dome Creek 1 1 320 0.18 - 63 - 5.2 Soil Classification and Pedon Characteristics Five pedons are classified as Eluviated Dystric Brunisois, two as a Gleyed Eluviated Dystric Bruniscis, five as Orthic Hum o-Ferric Podzols, two as Orthic Gray Luvisols, and one as a Rego Humic Gieysol. In the USD A Soil Taxonomy, eight pedons are classified as Typic Haplocryods, three as Typic Cryochrepts, one Oxyaquic Cryochrept, one Typic Cryoboralf, one Typic Cryaquod and one Oxyaquic Cryoboroll. Table 5.2 is a summary o f the classifications for each o f the study pedons. Table 5.2 Soil Classifications for each o f the situdy pedons. Pedon Canadian Syaton. e t SoB Cbuattcaffen VSBA SottXns.oiioaiy 1 Eluviated Dystric Brunisol Typic Cryochrept 2 Orthic Hum o-Ferric Podzol Typic Haplocryod 3 Eluviated Dystric Brunisol Typic Cryochrept 4 Eluviated D ystric Brunisol Typic Haplocryod lililli Orthic Gray Luvisol Typic Cryoboralf 6 Gleyed Eluviated Dystric Brunisol Typic Cryaquod 7 Orthic Hum o-Ferric Podzol Typic Haplocryod Orthic Hum o-Ferric Podzol Typic Haplocryod 9 Orthic Hum o-Ferric Podzol Typic Haplocryod 10 Gleyed Eluviated Dystric Brunisol Oxyaquic Cryochrept 11-U Orthic Gray Luvisol Typic Haplocryod I l- M Eluviated D ystric Brunisol Typic Haplocryod 11-lL Rego Humic Gieysol O jyaquic Cryoboroll 12 Eluviated Dystric Brunisol Typic Haplocryod 13 Orthic Hum o-Ferric Podzol Typic Cryochrept U = upper slope, M - mid-slope, L = lower slope - 64 - Each o f the sites have similar soil moisture and temperature regimes because the study site selection was designed to minimize environmental dififerences between the different plots. W ith the exceptions o f the m icrosite variation o f the lower slope position o f Site 11, all sites have udic m oisture regimes as defined within the Keys to Soil Taxonomy, Sixth Edition (Soil Survey Staflf, 1994). Also, each o f the sites has a cryic soil temperature regime as determined by the calculations defined in section 4.4. 5.2.1 The Eluviated Dystric Brunisois Pedons I, 3, 4, 11 (middle slope) and 12 are classified as Eluviated Dystric Brunisois (E.DYB) (Typic Cryochrept and Typic Haplocryods). These soils have an Ae horizon and Bm (BQ or Btj) horizon with pH ccc < 5.5. The p H ^ o ranges from 3.9 to 5.7, increasing from the A through C horizons in each o f the pedons. The clay content is consistetitly below 10% throughout each o f these pedons with the exception o f Pedon 4 which ranges between 15.2% and 18.6% from the Ahe to the C horizon. The cation exchange capacity (CEC) is less than 9 cmol(+) kg'* in all o f the horizons with the highest CEC in the A horizon o f Pedon 1 (8.9 cmol (+) kg'*) and the lowest in the BC, IC and EC horizons Pedon 11 (middle slope) (CEC =1.1 cmol (+) kg'*). The B horizons o f the E.DYBs have CEC betw een 3.8 cmol(+) kg'* and 7.0 cmol (+) kg'*. The exchange complexes are dominated by Ca, A1 and M g w ith base saturations ranging from a low o f 9.5% in the B horizon o f Pedon 4 to a high o f 85% in EC horizon o f Pedon 11 (middle slope). The sum o f sodium pyrophosphate extractable Fe + A1 (Fe, + A(,) ranges from < 0.1% in the A horizons to 0.22% 0.44% in the B horizons. The properties o f these pedons do not meet the criteria o f any o f the diagnostic horizons - 65- within the Canadian System o f Soil Classification (Agriculture Canada Expert Committee on Soil Survey, 1987). The results for the analysis o f Pedon 1 are provided as an example o f an E.DYB soil profile found within this region, including a photograph, a field description and selected physical/chemical properties (Figure 5.1 and Tables 5.3 and 5.4). The results for the remaining E.DYB pedons are in Appendices B (profile descriptions and diagnostic horizons/properties) and C (physical and chemical properties). Having been mapped as members o f the Dominion and Averil association and the Bearpaw Ridge and Captain Creek association, it was anticipated that Pedons 1 , 3 , 4 and 10 would be dominated by Orthic Humo-Ferric Podzols (O.HFP) with a significant inclusion o f E DYBs. In the case of Pedons 11 and 12, in which the Barton association is mapped, Orthic Ferro-Humic Podzols were expected. However, the distinction between the Brunisolic and Podzolic Orders within the Canadian System o f Soil Classification results mainly fi*om the podzolization process. Eluviated Dystric Brunisois do not have a sufiScient amount o f FCp and A^ to meet the requirements for a podzolic B diagnostic horizon (Agriculture Canada Expert Committee on Soil Survey, 1987). With time, these E.DYB pedons may develop into podzolic soils as shown in the properties o f Pedons 4 and 11 (middle slope) which show a degree o f podzolization based on their classification in the USD A Soil Taxonomy (Soil Survey Staff, 1994). Pedons 4 and 11 (middle slope) have values for ammonium oxalate extractable Fe and A1 (Feo and Al„ ) and an optical density o f oxalate extract (ODOE) indicative o f some degree o f podzolization (Appendix B). These two pedons are classified as Typic Haplocryods in the order Spodosols (the equivalent to the Podzolic Order) in Soil Taxonomy (Soil Survey Staff, 1994). The ODOE is an indication o f a podzolization process because it extracts organic complexes o f Fe and - 66- Figure 5.1 Profile o f Pedon 1, mmElaviated D ystric BrunisoL - 67 - T able 5.3 Horizon Pedon 1 - Profile description, diagnostic horizons and/or properties typical o f Depth fcm) S Bryophytes La 5-4 Deciduous leaves, coniferous needles, twigs, fungal mycelia. Foi 4-2 Moist; black (SYR 2.5/1 m); moderate, compact matted, friable, leafy; few, fine roots; common, random fungal mycelia. H t 2-0 Moist; (5YR 2.5/1 m); strong, granular, finable, gritty; common, very fine roots; few, random fungal mycelia. Ae 0-11 Very dark grayish brown (lOYR 3/2 m); silt loam; strong, fine granular, finable; abundant, fine to coarse, random, inped and exped roots; charcoal fragments; clear, smooth boundary. Bfjl 11-19 Strong brown (7.5YR 4/6 m); loam; moderate to strong, fine, subangular bloclqr, slightly finable; abundant, coarse to medium, verticaf inped and exped roots; gradual, smooth boundary. BQ2 19-32 Dark brown (7.5YR 3/4 m); loam; moderate to strong, fine, subangular blocky; slightly fiiable; plentiful, medium to coarse, vertical, inped and exped roots; gradual, smooth boundary. BC 32-43 Dark yellowish brown (lOYR 4/4 m); loam; moderate to strong, fine, subangular blocky, moderately finable; few, fine to medium, vertical, exped roots; gradual, smooth boundary. C 43+ Very dark grayish brown (2.5Y 3/2 m); loam; very weak, medium, subangular bloclqr, slightly hard; very few, fine, vertical, exped roots. Diagnostic Horizons and/or Properties. Canadian System: BÇ horizon. pH<5.5by0.01M CaCfy Ae horizon at least 2 cm thick. Eluviated Dystric Brunisol. U.S. Soil Taxonomy: Epipedon; Ochric Subsurface horizons: Albic, Gambie. Subsurface materials: Albic. Typic Cryochrept. - 68- Table 5.4 le MMF. ll l i l s î i i l l l l i l % 54.5 49.8 49.7 53.6 51.8 Clay AI Ca iiiïiilii c 0.022" 0.022* 0.16 0.30 0.19 3.1 2.8 1.8 1.5 0.89 0.011" 0.011" 0.011" 0.011" 0.011" HORIZON Al, ■111 % 0.073 0.33 0.26 0.19 0.067 0.041 0.21 0.26 0.32 0.18 HORIZON Ae m BQ2 BC C BQt A« ' Bm im m m m BC „ = (NH4)2C204 % 0.024 0.13 0.17 0.20 0.10 N C/N % 0.13 0.14 0,10 0.086 0.056 pH m o pH O.OIM CaCI, 15 17 18 20 14 4.6 5.2 5.3 5.5 5.7 3.6 Extractable Catinns by NBLOAc p K7,0 (cmulWktt') Mb fe # # # # # Na CEC % 40.4 46.2 47.0 42.7 42.3 5.10 4.00 3.30 3.70 5.90 HOmZQN iiiiliiiiiil Texture Clans m B Ê Ê Ê m = Nh4P207 sandy loam sandy loam sandy loam sandy loam sandy loam % 1.9 2.3 1.9 1.7 0.76 4.4 4.6 4.6 4.8 Baie Sat* 0.15 0.0050* 0.0050" 0.13 0.084 1.1 1.2 0.60 0.36 0.17 0.0070" 0.0070" 0.0070" 0.0070" 0.0070* 0.059 0.026 0.045 0.033 0.021 8.9 7.0 4.1 3.4 1.6 % 50 56 60 60 75 Fe. ODOE* F«p +Alp (Fcp+Alp) /clay erg C/Ffp 5FC.+AI, •/• 0.085 0.26 0.13 0,096 0.036 0.63 1.6 1.2 1.1 0.26 0.097 0.46 0.42 0.39 0.17 0.019 0.12 0.13 0.10 0.029 26 0.083 0.34 0.32 0.37 0.20 * = optical density o oxalate extract 7.1 7.0 9.1 11 H_= result lower than this detection limit Al as well as the amorphous inorganic Fe and A1 believed to be associated with imogolite, protoimogolite and ferrihydrite (Daly, 1982; Wang, 1990). Recently, the formation of these inorganic amorphous Fe, A1 (and Si) materials have been recognized as a major occurrence within podzolization processes in addition to the movement o f organic matter with or without Fe and Al. In the USD A Soil Taxonomy, pedons 1 and 3 are classified as Typic Cryochrepts within the order Inceptisols (the equivalent of the Brunisolic Order in the Canadian System). Bums (1990) noted that high elevations and cold temperatures could slow biological and chemical processes to the point where illuviation o f organometallic compounds would not be able to take place leading to the classification o f Brunisois rather than Podzols. 5.2.2 The Orthic Humo-Ferric Podzols Pedons 2, 7, 8, 9 and 13 are classified as Orthic Humo-Ferric Podzols (Typic Haplocryods and Typic Cryochrept). These pedons are more acidic than the Brunisois as the pHcacc consistently lower than the Brunisois ranging between 3.2 and 5.1 (pHjH2o ranges from 4.2 - 6.1). The maximum clay content o f the OHFPs is 10.4% in Pedon 13 and is less than 3.5% in the majority of horizons. The CEC is less than 10 cmol(+) kg'^ in all but Pedon 13 which ranges from 12 cmol(+) kg'^ to 18 cmol(-r) kg'*. For the remaining O.HFPs, the B horizons have the highest CEC ranging from 3.4 cmol(+) kg'* in the B£2 horizon o f Pedon 2 to 7.5 cmol(+) kg'* in the B f horizon o f Pedon 9. The CEC for the Ae horizons ranges from 2.3 cmol(+) kg'* in Pedon 8 to 9.9 cmol(+) kg '* in Pedon 9 compared to a range o f 1.3 cmol(+) kg'* to 2.7 cmol(+) kg'* in the C horizons (Pedon 9 and Pedon 2, respectively). Calcium is the dominant exchangeable cation o f the O HFPs with Mg providing the second highest levels. The remaining cations contribute to the exchange complex to -70- a much lesser degree with many Fe and Mn values being below the detection limit of the laboratory equipment. Our results for exchangeable Ca, Mg and K are comparable to the figures presented by Kimmins and Hawkes (1978) in their study o f post-harvest nutrient levels on podzols within the SBS zone northeast o f Prince George. (However, our values for the Ae horizon are m arginally higher than their reported values and our B horizon values tend to be lower than theirs.) Base saturation ranges fi-om a low o f 8.4% in Pedon 9 to fiiU saturation in Pedon 13. FOp values are above 0.3% and the sum o f Fep + Alp are above 0.6% as required for the diagnostic podzoUc B horizon within the Canadian System o f Soil Classification (Agriculture Canada Expert Committee on Soil Survey, 1987). Pedons 2, 7 and 8 have been mapped within the Averil 1 and Dominion 2 soil associations, though to differing degrees o f each association. These Podzols are shown to have a smaller range o f textures than the Brunisois within these associations as the Podzols range in texture fi-om loam to sandy loam with sandy loam again being the dominant texture class. This is consistent with the particle size class o f the parent materials reported for these areas (Dawson, 1989). Site 9 is part of the Torpy River 2 and Dome Creek 1 associations; these are moderately well to rapidly drained soils which are expected to develop into Eluviated Dystric Brunisois and Orthic Humo-Ferric Podzols. Site 13 is within the Dezaiko 2 and Captain Creek 2 associations which are dominated by Orthic Humo-Ferric Podzols. Chemically, these pedons are similar to the E.DYBs but with a stronger degree of podzolization. Humo-Ferric Podzols are common on steep slopes in the interior o f British Columbia (Young and Alley, 1978) and primarily are distinguished fi-om the other Podzols by their higher Fep than observed in the Bh horizon of the Humic Podzols or the Bhf o f the Ferro-Humic Podzols. -71- These other Podzols also occur under wetter conditions than the Humo-Ferric Podzol as the Humic Podzol may be found under saturated conditions and the Ferro-Humic Podzols are usually found under more humid conditions, such as on the coast o f British Columbia. The Orthic Humo-Ferric Podzol is the modal soil for the Humo-Ferric Podzols. It is distinguished from the other HumoFerric Podzols by its light coloured A horizon, its lack o f a cemented, duric, fragic or placic horizon as well as its lack of mottling or a Bt horizon within the top 50 cm o f its profile (Agriculture Canada Expert Committee on Soil Survey, 1987). Figure 5.2 is a photograph o f Pedon 8 and is provided as an example o f the O HFPs which may be found in the region. The profile description and physical/chemical data for Pedon 8 are provided in Tables 5.5 and 5.6 and are representative o f the other O.HFPs. Profile descriptions and results o f the physical and chemical analyses for the remaining pedons have been provided as Appendices B and C. Pedons 2, 7, 8 and 9 are all classified as Typic Haplocryods within the USDA Soil Taxonomy. This was anticipated as these belong to the Spodosol Order which, as has been previously mentioned, is the equivalent to the Podzolic Order in the Canadian System. However, Pedon 13 is classified as a Typic Cryochrept. In this case, the properties are not suflBcient to satisfy the requirements of a spodic horizon; ODOE was above 0.25, but does not increase with depth, and the value of 0.5Feo + Al„ is below 0.5%, the minimum requirement. 5.2.3 The Orthic Gray Luvisols Pedons 5 and 11 (upper slope) are classified as Orthic Gray Luvisols (Typic Cryoboralf and Typic Haplocryod). These pedons have Ae and Bt horizons. The pHccu ranges from 4.1 to 5.2 -72- Figure S.2 Profile o f Pedop 9, mn Orthic Hnino-Fcrric PodzoL -73- Table 5.5 Horizon Pedon 9 - Profile description, diagnostic horizons and/or properties typical of an Orthic Humo-Ferric Podzol found within the MMF. Depth fcm> Deacriollott S Bryophytes. Lv 6-4 Deciduous leaves, twigs, coniferous needles, fungal mycelia. Fm. 4-2 Moist; black (lOYR 2/1 m); weak, compact matted, firm, fibrous; few, very fine roots; cotamoa Annelida', common, random fungal mycelia. Hr 2-0 Moist; very dark brown (lOYR 2/2 m); moderate, compact matted, firm, fibrous; common, very fine roots, coxamonAnnelida', few, random fiingal mycelia. Ae 0-10 Light brownish gray (lOYR 6/2 m); silt loam; moderate, medium, subangular blocky, slightly hard; plentiful, medium, vertical, exped roots; clear, wavy boimdaiy. Bf 10-33 Yellowish red (5YR 4/6 m); silt loam; strong, fine to medium, subangular blocky slightly hard; plentiful, medium to coarse, vertical, exped roots; gradual, wavy boundary. BC 33-48 Dark yellowish brown (10 YR 4/6 m); loamy sand; single grain; loose; plentifiü, medium, vertical, exped roots; gradual, smooth boundary. C 48-t- Yellowish brown (lOYR 5/8 m); loamy sand; single grain; loose; very few, fine and medium, vertical, exped roots. Canadian System: Podzolic Bf horizon. Organic C = 0.5-5% FCp-i-Alp = 0.6% or more. Base saturation < 50% Orthic Humo-Ferric Podzol. U.S. Soil Taxonomy: Epipedon: Ochric Subsurface horizons: Albic, Spodic. Subsurface materials: Albic, Spodic. Typic Haplocryod. -74- HBsaE8^s8a3SEa@®™B5^ffiss^BBsrass!sssÊSâa5Ssia$s^^ssa3^^@as^5sss^smæîë^^mssagSî^ HORIZON Af Bf BC C Sand Clay Silt % 32,6 55,5 84.2 86 % 7 3 1.8 1.6 % 60.4 41.5 Al Ae Bf 0,44 0.59 iiiiiiiii 0.4 0.24 Ae Pililiiii iiiiiiiii " C' = (NH4)zC20^ Texture Class silt loam sandy loam loamy sand sand/ loamy sand Extractable Catkms by NH.OÀC p #7.0 HORIZON HORIZON 14 12.4 u M te S e k S È ïa ü ^ ^ ii # % 0.49 3.4 1.3 1.4 % 0.010" 0.099 0.062 0.057 C/N 98 35 21 24 pH pH dH ,0 0.01MC«C1, 4.2 4.7 4.8 5 3.2 4 4.3 4.4 Base Sat (cmoK+)kf') Mt Mn Na CEC 0.011" 0.042 0.011* 0.011" 0.16 O il 0.0050" 0.044 0.24 0.074 0.017 0.014 0.048 0.010 0.0070" 0.0070" 0.022 0.028 9.9 7.5 2.2 1.3 % 19 9.4 8.4 14 iiiiliiiiiil orgC/Fep SFc.+AI, 0.34 0.34 0.08 2.7 0.87 0.65 0.033 0.95 0.28 0.33 (Fe,+A y /clay 0.005 0.14 0.16 Fe. % 0.023 0.42 0.13 O il ODOE" 0.014 0.63 Alp % 0.048 0.61 34 5.4 9.5 8.5 0.059 0.82 0.41 0.39 Fep % p = Na^P^O? N K # # # 1.5 0.49 0.15 0.1 0.019 0.31 0.14 0.17 C * = optical density of oxalate extract 0.014 0.017 0.32 0.15 0.21 (p H ^ o 4.7 to 6.4) in Pedon 5 and from 3.5 to 4.2 (pH^^o 4.3 to 4.7) in Pedon 11 (upper slope). The CEC is below 10 cmol(+) kg'^ in both pedons with the highest levels in the Bt horizon o f Pedon 5 (9.9 cmol(+) kg ‘) and the lowest levels in the BC and C horizons (2.9 cmol(+) kg’^ and 1.6 cmoI(+) k g '\ respectively) o f Pedon 11 (upper slope). Calcium again is the dominant cation ranging from 0.25 cmol(+) kg*^ in the C horizon o f Pedon 11 (upper slope) to a high o f 5.3 cmol(+) kg‘‘ in the BC horizon o f Pedon 5. Base saturation is lowest in Pedon 11 (upper slope) with values not exceeding 34% and highest in Pedon 5 ranging from 37% in the Bt horizon to full saturation in the C horizon. Properties representative o f lessivage are used in the classification o f these pedons. Clay levels increase from 5 - 12% from the Ae to B tl horizons in Pedon 5 and from 7.9 - 13.4% from the Ae to Bt horizons in Pedon 11 (upper slope). Since clay levels do not exceed 15% in either pedon, an increase from the A to B horizon o f only 3% clay fraction is required to classify the B horizon as a Bt horizon, a characteristic o f the Luvisolic Order (Agriculture Canada Expert Committee on Soil Survey, 1987). The classification o f Pedon 5 is unique as both the B tl and Bt2 horizons show considerable translocation o f FCp and Alp. If not for the change in clay levels between the Ae and B tl horizons, both of the Bt horizons would be classified as podzolic B horizons. However, within the Canadian System, the presence o f a Bt horizon within the top 50 cm o f the soil profile rules out the podzoUc order (Agriculture Canada Expert Committee on Soil Survey, 1987). Pedon 5 also is found to belong to polygon 232 o f the McGregor Soils ARC/INFO Database. This polygon is derived from a combination o f the Dominion 2 (70%) and Averil 1 (30%) soil associations which are discussed in section 2.2. If not for the luvisolic properties o f this pedon, the dominant Orthic Humo-Ferric Podzol classification o f these associations would have been keyed. -76- Pedon 5 demonstrates a similarity between the American and Canadian systems o f soil classification. Within the Canadian System, the Bt horizon (illuviation o f clay) supersedes the podzolic B horizon (translocation of FCp and Alp) leading to the Luvisolic Order (Agriculture Canada Expert Committee on Soil Survey, 1987). Similarly, the presence o f the argillic diagnostic subsurface horizon prevents keying within the Spodosols in the Soil Taxonomy and leads to the keying within the Alfisol Order (Agriculture Canada Expert Committee on Soil Survey, 1987; Soil Survey Staff, 1994). The classification o f Pedon 11 (upper slope) demonstrates a difference between the Canadian and American approaches to classification. However, in the Soil Taxonomy, the argillic diagnostic subsurface horizon must be above the spodic diagnostic subsurface horizon in order to rule out the podzolization in keying the classification (Soil Survey Staff, 1994). In the case o f Pedon 11 (upper slope), the Bt horizon is diagnosed as having both argillic and spodic properties leading to the keying o f the Spodosol Order before the Alfisol Order could be keyed. A photograph (Figure 5.3), profile description and physical/chemical data (Tables 5.7 and 5.8, respectively) for Pedon 5 follow as a representation o f an O.GL which may be found within the MMF. The profile description and physical/chemical data for Pedon 11 (upper slope) are provided in Appendices B and C, respectively. 5.2.4 The Gleyed Eluviated Dystric Brunisois and the Rego Humic Gieysol Pedons 6 and 10 are classified as a Gleyed Eluviated Dystric Brunisois (GLE.EDB) and Pedon 11 (lower slope) is classified as a Rego Humic Gieysol (R.HG). These gleyed pedons result from changes in microtopography. Pedons 6 and 10 meet all the aforementioned physical and -77- Figure S 3 Profile o f Pedon S, «tt Orthic Gray LavisoL •78“ Table 5.7 Pedon 5 - Profile description, diagnostic horizons and/or properties typical of Hodzoti Dep& fcm> Lv 7-6 Hr 6-0 Deacriiaioo Twigs, deciduous leaves, coniferous needles. Moist; black (lOYR 2/1 m); weak, granular, firm, greasy; abundant, fine roots; few M yriapoda\ few, random droppings. Ae 0-15 Grayish brown (10 YR 5/2 m); sandy loam; single grain; loose; abimdant, coarse, random, exped roots; clear, wavy botmdaiy. Btl 15-35 Dark brown (7.5YR 3/4 m); loam; strong, fine to medium, subangular blocky; fiiable; plentiful, fine to coarse, random, exped roots; clear, wavy boundary. Bt2 35-55 Strong brown (7.5YR 4/6 m); sandy loam; moderate, fine to medium, subangular blocky; fiiable; plentiful, medium, verticaL exped roots; gradual, wavy boimdary. BC 55-69 Dark brown (lOYR 3/3 m); loamy sand; moderate, medium, subangular blocky; slightly fiiable; plentiful, fine to medium, vertical, exped roots; gradual, smooth boundary. C 69+ Olive brown (2.5Y 4/4 m); sand; massive; slightly hard; many, fine to medium, vertical, exped roots. Diagnostic Horizona and/or Propcrtiea. Canadian System: Bt and eluvial horizons. Medium to fine textured soils. Orthic Gray Luvisol. U.S. Soil Taxonomy: Epipedon: Ochric Subsurface horizons: Albic, Argillic. Subsurface materials: Albic. Typic Cryoboralf. -79- Table 5.8 Pedon 5 - Selected physical and chemical properties of an Orthic Gray Luvisol found within the MMF. illiiliili C/N # 00# # % 1.1 4.5 4.2 4.1 1.4 0.064 0.2 0.1 0.35 0.11 18 23 42 12 12 5,3 4.7 5.3 6.2 6.4 Me Mn Na CEC 0.11 0.18 0.1 0.038 0.01 1.9 1.6 1.3 0.99 0.94 0.011 0.011 0.015 0.0070* 0.0070* 0.013 0.026 0.033 0,02 0.014 7.9 9.9 7.6 6.6 4.7 % 84 37 65 96 saturated AL Fe, ODOE* Fe,+A l, (Fe,+AV) /clay erg Cfftp SFe,+AI, % 0.013 0.45 0.68 0.48 0.099 0.012 0.56 0.21 0.084 0.037 0.50 3.2 3 2.4 0.43 0.013 0.89 1.1 0.48 0.13 0.003 0.071 0,11 0.081 0.020 140 7.2 6.4 21 23 0.019 0.73 0.79 0.52 0.12 HORIZON Sand Clay Silt Texture Class C Ae % 59,8 54.6 57.7 71.8 75.7 % 5 12.6 10.4 5.9 6.4 % 35.2 32.8 31.9 22.3 17.9 .sandy loam sandy loam sandy loam sandy loam sandy loam Al Ca 0.022* 0.15 0.41 0.048 0.022* 4.6 1,9 3.5 5.3 4.2 0,011* 0.044 0.023 0.011* 0.011* % % 0.005 0.260 0.467 0.289 0.07 0.008 0.63 0.65 0.19 0.059 Btl Bt2 'mÊ^ÊÊm HORIZON Ae B tt iiiiiiii Iiiiiiiii c HORIZON Ae B tl Bt2 BC o = (N H 4 > 2 C 2 0 4 . = N a4 P 2 0 2 Extractable Catians by NHLOAc p Fe K * = optical density o oxalate extract pH O.OIMCaCI, 4.5 4.1 4.6 5.2 5.2 Ba#e$at result lower than this detection limit chemical requirements o f E.DYBs, however, mottling was observed in both the B and C horizons and water seepage was noted in a sand layer at a depth o f 59 cm leading to the belief that periodic water saturation is a permanent feature o f Pedon 6 and mottles were noted in the C horizon o f Pedon 10. These pedons have pHcacu between 3.8 and 5.1 and p H ^ o &om 4.5 to 6.2 increasing from the Ae to the Cg horizons. The clay content o f these pedons was highest in the BQ horizon (6.00%) of Pedon 10 and lowest in the Cg horizon (4.60%) o f Pedon 6 . As with all the E.DYBs and O HFPs, Ca is the dominant cation in the exchange complex. Exchangeable Al and Fe are below detection limits in most horizons and exchangeable Mn is below the detection limit in the Btjg horizon of Pedon 6 and the Cg horizons o f both pedons. CEC levels are similar to the E.DYBs ranging from 2.4 cmol(+) kg‘‘ to 8.9 cmol(+) kg'\ Base saturation ranges from 32% to frill saturation. Fep values do not exceed 0.35% and Fep+Alp values do not exceed 0.44% in any o f the horizons. Pedon 11 (lower slope) is classified as a Rego Humic Gieysol. A digitized photograph, profile description and physical/chemical data are provided as Figure 5.4, Table 5.9 and Table 5.10. The pH, CEC and base saturation levels for this pedon are all higher than the majority o f the E.DYB, O.HFP and O.GL values. This is an azonal soil which formed on coUuvium at the base of a relict avalanche of which Pedon 11 (upper slope) and Pedon 11 (middle slope) are a part. The accumulated organic matter which came to rest at this point from the upper slope positions is a primary factor in leading to this classification. While this classification may not be dominant on the landscape of the study area, Humic Gleysols can be found in depressions below Humo-Ferric Podzols where seepage is extensive and water has been able to accumulate (Young and Alley 1978). King and Brewster (1978) demonstrated that environmental stresses occurring during the period of pedogenesis can change the pathway that a developing soil will follow. Their study showed the - 81- Figure 5.4 Profile of Pedon 11 (lower slope), a Rego Humic CleysoL W -82- . Table 5.9 Pedon 11 (lower slope) - Profile description, diagnostic horizons and/or Horizon Deothfcm^ Ln 16-14 Deciduous Leaves, coniferous needles, twigs. Fa 14-8 Moist; black (lOYR 2/2); strong, non-compact matted, resilient, fibrous; common, fine roots; few Deanna; common droppings; common fimgal mycelia. Hh 8-0 Moist; black (lOYR 2/2); strong, non-compact matted, firm, fibrous; abundant, very fine roots; few.4can>ja, few Myriapoda- common droppings; common fungal mycelia. Ah 0-20 Dark reddish brown (5YR 2.5/2 m); silt loam; moderate, fine to medium, granular; loose; plentiful, fine, vertical, inped roots; clear, wavy boundar)i 10-25 cm thick. ACg 20-40 Brown (7.5 YR 4/3 m); sandy loam; weak, fine, granular, very fiiable; few, fine, horizontal, inped roots; clear, wavy boundary; 20-30 cm thick. Cg 40+ Brown (lOYR 4/4 m); sandy loam; weak, fine, granular; very fiiable; very few, medium, horizontal, inped roots. Water seepage at 75 cm. OescdPtKM Diagnostic Horizons and/or Propertic». Canadian System: Water table at 75 cm. Ah at least 10 cm thick overlying Cg horizon. Rego Humic Gieysol. U.S. Soil Taxonomy: Epipedon: Molhc Subsurface horizons: None. Subsurface materials: None. Oxyaquic Cryoboroll. O ther Site Characteristics: Aquic moisture regime. Episaturation. -83- Table 5.10 Pedon 11 (lower slope) - Selected physical and chemical properties of a Rego Humic Gieysol found north of the MMF. Clay HORIZON i iiiiïiii % 40.2 % 6.6 % 53.2 ACg Ce 80.7 74.4 2 2 17.3 23.6 Texture Class N C/N W ÊÊÊÊÊi silt loam 3.1 % 0.23 14 6 loam y sand 3.5 loam v sand 3.9 0.25 0.28 14 14 6.3 6.5 117,0 fcmoK+)l«r’l HORIZON AI 0.022* 0.022* m Sm Ê Ê m 16 Fe 0.011* 6.5 0.032 6.8 0.011* 0.011* K 0.057 0.0050* 0.16 Ah Ai, % 0.046 Fe, % 0.061 iiiiiiiii Cs 0.17 0.15 „ = (N H^)jCjO ^ p = N a^P jO , Ah HORIZON Ms 1.3 Mo 0.078 0.028 0.49 0.5 0.010 OBOE* Fe^+A), 0.081 Fe, % 0.063 0.10 0,11 0.27 0.22 0.13 2.5 0.21 0.21 0.096 1.7 0.44 0.36 * = o p tical density o f o x alate e x tract pH O.OlMCaCI, 5.4 5.6 5.7 Na 0.031 CEC 20 Base S a t % 87 0.032 0.009 7.6 6.8 94 saturated (Fe, +AI,) /day 0.067 arg C/Fe, ,$Ft,+AI» 5,1 0,11 0.18 12 0,28 0.31 17 0.25 = result lower than this detection limit creations o f Eutric Brunisols, Hnmo-Ferric Podzols, Ferro-Humic Podzols and Orthic Regosols from the same parent material. Perhaps the most unique classification o f the fifteen pedons is Pedon 11 (lower slope) being classified within the Soil Taxonomy’s Mollisol Order. This pedon is not shown to meet the requirements for a Chemozemic A horizon due to its moisture regime not being drier than humid (Agriculture Canada Expert Committee on Soil Survey, 1987). This is not the case with the Soil Taxonomy classification as the Ah horizon meets the requirements o f a moUic epipedon. This order is representative o f grassland ecosystems and is not expected within a forested environment. I f not for the epipedon, this pedon would have been classified within the Inceptisol Order along with the other Brunisols (Soil Survey Static 1994). 5.3 Nitrogen Concentrations and Age Class Analysis Our results show distinct difterences between the mineral horizons and the forest floor horizons; the forest floor horizons contain considerably higher levels o f all forms of nitrogen studied. This is noted in other studies (such as Sveinbjomsson et al., 1995). Table 5.11 provides a summary of the mean values obtained for each o f the sites. The complete data set from the nitrogen analyses is provided in Appendix D. The results o f the Kruskal-Wallis H-Test Statistics and Fisher’s LSD have been compiled in Table 5.12 and the results from the General Linear Model (GLM) are presented in Table 5.13. The results o f these tests will be discussed separately in subsections 5 .3 .1 5.3.4. -85- Table 5.11 Site Mean values of the results obtained from the nitrogen analyses for each study Total M io-N (ppm) îîOjrCiïimt) CAT Rati» A+B F.F. A+B F.F, A+B F,F, A+B F^, A+B ¥,W, 1 0.127 1.81 2.31 8.38 6.65 117 39.6 1020 23.8 23.1 2 0.177 1.54 4.04 0.894 11.4 268 32.9 852 17.4 27.1 3 0.219 1.7 0.08 0.522 9.01 141 24.5 1160 16.7 20.7 4 0.152 1.62 1.08 0.467 14.2 97 30.5 1080 17.4 24 5 0.144 1.47 4.84 19 11.3 62.7 37.8 434 39.6 24.7 6 0.09 1.87 10.9 91.5 4.81 156 34.3 815 22.1 21.5 7 0.232 1.58 1.17 1.17 8.64 363 43.1 1270 14.5 23.9 8 0.136 1.87 15.3 18 11.2 287 56.7 1620 31.8 24.2 9 0.126 0.963 6.2 8.37 6.18 194 36.1 610 19.1 43.3 lllllilll 0.09 1.66 7.59 81.3 10.1 294 33.3 807 31.9 29.2 0.09 1.43 1.11 0.887 6.21 108 27.7 1110 18.4 24.3 0.138 1.57 0.1 0.4 7.33 94 30.1 728 15.5 25.9 0.162 2 8.98 108 4.33 43.9 37.8 520 21.8 19.2 0.145 1.65 4.9 26.6 8.56 182 35.7 927 27.2 25.8 12 Overall Mean -86 - Table 5.12 Horizon Kruskal-Wallis H-Tcsts and Fisher’s LSD Tests for significant differences of the ranked mean nitrogen levels between age classes for each forest floor and Total N Available NO» Avadahie NH/ Mineralizable N C/NRatio H=1.30 H=9.55 E* fvf L” H=6.08 E M L" H=7.72 E M L" H=3.19 H=0.380 H=9.83 E* M" L' H=0.630 H=3.55 H=4.95 H H=1.51 H=9.74 E* L" H=3.23 H = ll.l E* M** L" H=3.74 A H=2.70 H=4.59 H=9.22 E* L** H=1.86 H=0.79 H=0.930 H=7.77 E' M"» L" H=9.16 E* W L" H=8.85 E* L’* H=6.75 E'M" L" * The critical test value with a df=2 is S.99 (Griffith and Amrfaein, 1991), beyond which a significant difference in tlie means of the ranked data is shown. Results have been adjusted for ties where required. E = Early Serai, M = Mid-Seral, L = Late Send. No significant differences are found between age classes within the same cell which have the same superscripted. While the H-Tests showed significant differences at a 95% confidence level, Fisher’s LSD did not. Since Fisher’s LSD is designed conservatively and the H-Test results are not far above the critical value, these results will be treated as not being significantly different (B. Zumbo, personal communication, 1997). Table 5.13 Results of the General Linear Model examining the interaction effect between N T ype df Seq. SS Adj. SS Adj. M S F Total N 8, 173 14024 14024 1753 2.82 Avail. NO; 8, 173 47457 47457 5932 3.34 AvaiL 8, 173 6105 6105 763 1.21 M in.N 8, 173 24275 24275 3034 4.71 C/N Ratio 8, 173 25887 25887 3236 1.35 * The critical test value with a df=(8, 173) is 2.03 (Griffith and Amrhein, 1991), beyond which a significant difiference in the means of the ranked data is shown. -87- 5.3.1 Total N The minimum mean value obtained for total N within the mineral horizons (combined A and B horizons) was 0.0900% and 0.232% was the maximum value (Table 5.11). For the forest floor horizons (combined L, F and H horizons), the minimum and maximum means were 0.963% and 2.00%, respectively. Our results have a slightly smaller range than the findings o f Klinka et aL (1994) in the dry and cold (SBSdk) and the moist and cold (SBSmc) Sub-boreal Spruce biogeoclimatic subzones, but are comparable to those o f Taylor et al. (1991) who conducted prescribed fire and mechanical site preparation studies on different sites within the moist and cool (SBSmk) biogeoclimatic subzone o f the Sub-boreal Spruce zone. Since their sites had been logged in 1968, their results are comparable to our Early Serai site results. Our results are much closer to their findings for the mineral horizons, though this is not the case for the forest floor horizons. While they also examined mesic sites, their dominant vegetation was within the hybrid spruce-oak fern site series. This variation in vegetation, as well as the drier climate compared to our sites, may account for the differences between the two studies. In the SBS near Prince Rupert, Macadam (1987) recorded similar forest floor horizon values, but total N values for the mineral horizons are much lower than our findings In their study northeast of Prince George, Kimmins and Hawkes (1978) recorded total N values very similar to our grand mean total N value o f 1.65% for our forest floor samples. Table 5.14 provides the total N concentrations (pooled values) for each o f the horizons by age class. As determined by the Kruskal-Wallis H-Tests (Table 5.12), there is no significant difference between the ranks of the means for each o f the different age classes for the L, F, H, A and B horizons. This could indicate that the levels o f total N are no longer affected by the fire event after - 88 - Table 5.14 Hotjzou Minimum, maximum, mean and standard deviations of Total N contents (%) by AgeCb$* Early Serai u MtefmiiM ______ 1 ______ - 0.735 Maxinmi» M em 1.59 i ^B M M Late Serai 9 ^-r-1 Early Serai 5 ! 11 Mid-Seral 1 ^^B ^^B ^^B Early Serai 0.664 1 2.31 ! 1 ^B B^ B B ^^B M M 1.68 — B m m 2.62 I I 1.84 1.6 I 1.91 , 1.72 1 10 ! 0.726 ! 2.05 ! 1.5 ! 1.36 1 2.34 , 1.78 ^bb — ^b b^b « 0.379 ^^B ^^B ^^B ^ B Bm ^^B ^^B ^ B B ^^^B ^^B ^ B BB B B ^^B I I 0.193 b ^b , 7 11 « 1 0.729 ^B ^^B ^^B ^^B ^^B ^^^B ^^B ^^B ^^B ^ B Bb Lm ^^B ^^B ^^B ^ B B ^^^B ^^B ^^B ^ B BB ^ B Mid-Seral ^^B « 0.478 «^B ^^B 1.52 ! 1.13 ! ^B ^ B BM MM M ^ Late Serai H 0.446 SUmdaW D$v##dw& ^^B » ^M - ^^B 1.56 Mid-Seral F B M > [ 1 0.0966 0.397 ^^B ^^B B M » ^^B « . 0.35 ^B ^^B ^ B BB ^B ^^B ^^^B ^^B « ^ B BB ^ B ^^B ^B ^B B ^ B ^^B ^^B ^^B ^^^B B M < ^^B ^^B ^^B ^^^B M B »^ B BM MM B B« Late Serai Early Serai A 11 , 1.1 1 2.41 , 1.63 , 0.322 16 ! 0.012 ! 0.258 ! 0.114 ! 0.0726 ^B ^ B B^ B B ^^B ^^B B ^ B BB ^ B ^^B ^^B ^ M »^ B B M^^B ^^B ^^B B ^ B ^^^B B B B ^^B B B B ^^B ^^^B 20 Mid-Seral 0.04 1 ^B ^^B ^B » ^^B B B B 16 Late Serai 16 Early Serai A ^B ^B ^^B Late Serai 1 0.005 ! 0.086 ^Lm B ^B 20 Mid-Seral ^^B 16 1 0.29 ^^B B ^B ^Lb B ^^B ^^B 1 0.314 1 0.13 . ! 0.356 ! 0.148 ! B M ^M ^M 1 0.593 , 0.205 ^^^B M MB B BM B ^^B ^^^B ^^B B^ B^ I 0.042 . 1 0.323 0.172 0.0729 0.0647 B M ^M ^M ^M « , ^M ^^M , 0.0629 ^^B B MB B M^B * ^ B B« 1 B B B 0.067 0.099 ^^^B M M ^^B B^ ^^B M M^^B m , 0.139 ^^B « 0.077 14 years (assuming that prefire levels are equivalent to the Late Serai levels). As noted in Chapter 3, one-third o f the total N content o f the SBS can be found within 30 cm of the forest floor (Macadam, 1987). Since no significant differences in total N are found in the forest floor or A and B horizons, this is a good indication that changes in total N concentrations during a fire event may be returned to pre-fire levels within a 14-year period following the event in the SBSvkl. This is in agreement with published findings as the replacement o f the total N to prefire levels has been shown to occur firom within a few months after the fire in Mediterranean-type environments (Kutiel and -89- Naveh, 1987) to a few years in some fir ecosystems in the American Pacific Northwest (Wells et aL, 1979). Unfortunately, regional data with which to compare our results examining the changes of nitrogen concentrations over time following wildfire is lacking; most o f the studies in this region have looked at post-fire conditions after logging and slash burning. Sampling procedures have been shown to affect post-fire total N results (Mroz et aL, 1980). They found that their top fisrest floor layers had sustained significant total N losses immediately after the fire, however, their lower forest floor horizons showed increases in total N (Mroz et aL, 1980). W hen the entire forest floor was examined, their statistical results are similar to ours in that they found no significant difference between the prefire and post-fire total N levels. They noted that studies that examined only the ash material following a forest fire would overestimate the losses o f total N which is not the case in our study. This procedural dichotomy does not affect our results as the L, F and H horizons were all examined. In examining the GLM for the ranked total N data using the results o f the age class analysis, a significant difference is found in the interaction effect between the forest age classes and the soil horizons. Further examination will be required to determine the factor(s) influencing this interaction. In their study, Reich et aL (1997) showed that soil type/parent material explained much o f the variation in annual N mineralization. Since our sites were found on different soil types (Table 5.2) and on different types o f parent material (Table 2.1), these differences might provide more information on the N transformations within the MMF, however, this requires further study which is not within the scope o f this thesis. -90- 5.3.2 Available NO, and N H / Our mean available NO, levels range from 0.0769 - 15.3 ppm in the mineral horizons and from 0.400 - 108 ppm in the forest floor (see Table 5.11). The available NH^^ ranges from 4.33 14.2 ppm and 43.9 - 363 ppm in the mineral and forest floor horizons, respectively. Taylor et aL (1991) reported NO," values between 1.0 - 1.4 ppm in their mineral horizon samples which are much lower than the majority o f our mean values, particularly when compared to our Early Serai sites which range from 4.84 - 10.9 ppm. Their 20-year-old site has more in common with our Mid-Seral sites (four o f our five sites have NO, levels between 0.077 ppm and 2.31 ppm). Forest floor findings reveal similarities between four o f our sites and the sites studied by Taylor et al. (1991), however, the majority o f our sites have much higher values. The data obtained for the available NO, and N H / (pooled by age class) are summarized in Tables 5.15 and 5.16, respectively. It should be noted that these results are based on single point measurements and represent a snapshot o f the nitrogen dynamics in the sub-boreal forest. Recently, concern has been raised that single point data may not be representative o f NO," levels in coniferous forests as nitrification (oxidation o fN H / to NO, ) from microbial activity is believed to be occurring at a rate faster than can be measured, thus revealing available nitrogen levels much lower than may actually be the case (Stark and Hart, 1997). However, our procedure reports the total amount of available NO, in the collected soil samples and does not infer rates o f turnover. If NO, is locked in microbial biomass, it still is unavailable to plants and does not undermine this research. It is believed that this new paradigm o f nitrogen retention in forest soils be examine with respect to northern ecosystems. -91- Table 5.15 Uorizott L* F* H* Minimum, maximum, mean and standard deviations of available NO, ' contents u AgeCiaM M Ittinunt M aximum M em Early Serai 181 65.3 Mid-Seral 165 47.9 Late Serai 3.7 1.23 Early Serai 5 I 2.6 I 119 ! 69.4 ! 48.6 Mid-Serai 11 1 0.005 I 164 , 27.7 , 52.1 Late Serai 7 1 0.005 I 1.5 1 0.721 , 0.605 Early Serai 10 Î 0.5 ! 209 ^ « a » Mid-Serai 11 I 0.005 ! ^ ^ a , ill 50.4 ^ ^ a ^ ^ a , 11 Late Serai 16 Early Serai ^a aaa a ^ a 20 Mid-Serai I 0.005 I ! 0.005 ! ^ L a a a^ a» ^ a » 1 0.005 18.5 67 I 6.45 13.6 ! 5.26 ^"a a» « ^ a ^ ^ a J^a a—a» a m a 1 12.2 1 ! 65.6 ^ ^ ^ a ^ aa ^aa ^ ^ a^ ^ a ^ L ^ a ^ ^ a a^ aa a m a ^iaa ^aa a^a ^ ^ a ^ ^ a ^^ ^a ^ ^ a ^ ^ a ^ ^ a A Stm duni D evW m 1.24 ^ ^ a^ ^ a ^ ^ a« , 34.9 a^ ^ a ^ ^ a^ ^ a^ ^ a ^aa « , 20.1 ! 5.51 ^ ^ aa a a a , « 2.95 ^a ^ ^ a ^ ^ a aa ^ ^ a a^ ^a ^ ^ a ^ ^ a a ^ a ^ ^ a ^^ ^a a^ a ^ ^ a ^ ^ a ^ ^ a a L ^ a ^ ^ a ^ a »^ ^ a o ^ a aiaa ^ a a ^ ^ a ^ ^ a aaa « 16 Late Serai 16 Early Serai B* ^a ^ a a ^a 0.005 ! 0.005 ^^ aa 20 Mid-Serai 1 aa 1 ^ aa 0.005 ^ aa ^^ aa aaa 1 ! ^^^a 1 ^^ ^a 16 I 0.005 I Late Serai * = H-Tests showed significant difierences between the age classes. 9.05 I 2.88 , 22 ! 10.2 ! aw aa aa ^^^a 11.8 aa 1 aa aa a^^a ^ aa 27.6 , aa aa 3.66 5.71 ^a , aa < ^ a 7.39 3 # 3.82 ^a , aa ^a a^ « 10.1 By Kruskal-Wallis analysis, the A horizon is the only one which is found not to have a significant difference between the ranked means o f the NO3*values. In each o f the other horizons, the Early Serai age classes are grouped separately from the Mid-Seral and Late Serai. Results for the forest floor show decreasing NO3 levels firom the Early Serai through the later serai age classes. Increased nitrification rates during and following the forest fires could be responsible for these increased levels in the Early Serai stage. Similar results were reported by Viro (1974) who found increased NO3 levels (up to three times the control levels) for six years following afire in a Fenno- -92- Table 5.16 Hojdzou Minimum, maximum, mean and standard deviations of available NH 4^ contents A feC btt* MWmwu* E a rly S e ra i L *...... M id -S e ra l _ _ 2 L _ . L a te S e ra i E a rly S e ra i M wAumu t:a:lh|:Î Mc« b Standard DevlaUtHK : : f ; : ! 176 107 1 5 ! 4 1 .5 ! 133 M id -S e ra l 11 I 8 9 .7 , 553 , 255 L a te S e ra i 7 I 66 , 538 , 226 | 202 E a rly S e ra i 10 —W ! 2 3 .2 ww MW WW ! 318 MW MW mw MW wm a 8 .7 1 , A* I H* 20 M id -S e ra l ^w MM L a te S e ra i , "^w 16 ( 1 .6 5 1 9 .7 5 MW WBW ^ ^ w «W a^w mw 2 , 1 5 .3 I I I 1 mw , 4 .1 6 3 .5 4 * = H -T e s ts s h o w e d s ig n ific a n t d ifie r e n c e s b e tw e e n th e a g e c la s s e s . Scandian spruce forest dominated by podzolic soils. It is well documented that the removal of overlying vegetation following a forest fire will increase soil temperatures, pH and the availability o f cations resulting in higher rates o f decomposition and mineralization (Feller, 1982; MacLean et al., 1983; Wells et a i, 1979). Microbial biomass has been shown to be a major source o f mineralized nitrogen following surface heating. The higher temperatures that may result fi-om the removal o f the duflF layer can lead to increased microbial activity which, in turn, can lead to an increased rate o f mineralization (Andison, 1994). This “assart eflFect” continues until the increased -93- nutrients are taken up by new plants, are immobilized by microbes or are used up in chemical reactions (Kimmins, 1997). On a site by site basis, four of our sites (Sites 6, 8, 9 and 13) have higher mean levels o f NO3* than NH4" in the mineral horizons; the remainder of the sites have more shows similar results in the forest floor horizons. than NO^ . Site 13 These sites are within the Early Serai age class(with the exception o f Site 8 which is Late Serai). Viro (1974) found that N H / levels can be 20 times higher than NO3 in the humus layer o f acidic Fenno-Scandian spruce forests. However, Viro (1974) also noted that NH,* levels dropped sharply during the first three years following a fire, not significantly increasing until after 12 years and not showing pre-fire levels until 50 years following the fire. Even though the mean NO, level for the A horizon o f the Early Serai sites is five times that o f the Mid-Seral sites and almost double that o f the Late Serai, no statistical significance could be demonstrated. A closer examination o f the NO, data using a boxplot (Figure 5.5) shows the range for the A horizon and indicates that the small sample size may be the major determinant o f the non­ significance. The even spread of the outliers in the Mid-Seral age class may be causing the KruskalWallis test statistic to accept the ranked data as being equally distributed. This may occur because an alternation between the age classes of the ranked data gives the appearance that the data is more thoroughly distributed than is actually the case. The Early Serai sites tend to have thicker H horizons than the older sites, however, the variation in the depths o f the forest floors between the different horizons is not statistically significant (fi-om Kruskal-Wallis analysis of the depths o f each o f the forest floor horizons based on age class). In theory, thicker forest floor horizons should yield more decomposing materials derived from the herbaceous and mossy plants found predominantly at the -94- younger sites although this can only be verified if further analysis o f the decay rates o f these plants is done. Figure 5.5 Boxplot of the A horizon NO, levels with the Earfy Serai (1), Mid-Seral (2) and Late Serai (3) age classes on the x-axis and the NO, levels (ppm) on the y-axis. 1 4 —< 12 — 10 — 8 — 6— 0 — A-N-RANK Results indicate that Site 6, the Gleyed Eluviated Dystric Brunisol, has some o f the highest NO3■ levels (A horizon = 5.75-12.4 ppm, B horizon = 9.55-14.1 ppm) o f our sites. Since NO 3' is negatively charged, leaching in groundwater may be seen as a natural sink which may be hindered at this location. Courtin et al. (1988) noted that laterally moving groundwater may actually act as a source o f available nutrients in a soil as they are being transferred within the system and not being lost from it. This appears to have been the case at this study site. This increased nutrient availability may be beneficial to plants tolerant of high water levels such as Epilobium angustifolium (55% cover at Site 6) as well as the few A bies lasiocarpa and Picea glauca x engelmannii seedlings which are -95- found at the site (MacKinnon et a i, 1992). The null hypotheses were rejected for the GLM for the ranked NO, The differences shown by the age effect were previously presented in the Kruskal-Wallis tests, however, this model confounds the analysis by indicating that age alone may not explain the differences between the NO, ' levels found in the different forest age classes. When the NO, * levels are ranked for the mineral horizons alone, then subjected to the same GLM as above, the results indicate that there is no significant difiference between the different age classes. However, this result may be spurious due to the high p value (0.442). This may be an indication that the observed variation in NO, ' levels is occurring in the forest floor horizons and is large enough to override the lack of variation shown in the mineral horizons given that the NO, ' levels o f the forest floor can be as much as 10 times higher than the mineral horizons. The analysis o f the ranked NO, ' for only forest floor horizons indicates a significant difference between the age classes, however, there is no significant difference between the horizons and the interaction effect between the age classes and horizons as the p values are 0.579 and 0.973, respectively. Available N H / levels are highest in the Mid-Seral age class for the forest floor samples and highest in the Late Serai age class for the mineral soil horizons. Significant differences are found between the ranked means o f available NH^^ in the A B and L horizons. Different trends are noted for the forest floor and mineral horizons. In the forest floor horizons, the N H / values are lowest in the Early Serai, highest in the Mid-Seral and intermediate in the Late Serai compared to an overall increase with time since the fire disturbance in the mineral horizons. While the H-Test for the L horizon does show a significant difference, this is not revealed by the LSD post-hoc test. Examination of the test values show that the H-Test result for this horizon -96- is slightly over the 95% confidence level (see Table 5.12). Since a marginal increase in the level o f probability would remove the significant difiference and since Fisher’s test does not show a difiference, the significance was ignored (B. Zumbo, personal communication, 1997). In both the A and B horizons, the Early Serai age classes are grouped with the Mid-Seral age classes by Fisher’s test. In the A horizon, the Mid-Seral age class is not shown to be significantly different firom the Late Serai age class. This indicates a steady increase in NH4" levels over time in the mineral horizons. This may be due to the decrease in the nitrification rate, though it is difiScult to confirm the statement based on single extractions and because o f the paucity of data on microbial activity (Stark and Hart, 1997). As the canopy trees grow and create more shade, lower soil temperatures are to be expected due to diminished insolation. The GLM analysis o f the interactions between forest age classes and soil horizons for the NH4" show significant differences between the ages and the horizons, however an interaction effect is not seen (Table 5.13). 5.3.3 M ineralizable N Mineralizable N represents the organically bound nitrogen in the soil which can be rendered available to plants. Our mean values for mineralizable N range between 24.5 ppm and 56.7 ppm in the mineral horizons and between 4 3 4 ppm and 1620 ppm in the forest floor horizons (Table 5.11) w hich are consistent with values firom unpublished studies in the SBS in this area (P. Sanborn, personal communication, 1997). Our values are much higher than those in the drier SBS subzones studied by Klinka et al. (1994) in which mean levels of 0.8 - 181 ppm and 187 - 310 ppm were reported for the mineral and forest floor horizons, respectively. Forest floor mean values fi'om white -97- spruce forests in interior Alaska were much lower being listed between 1 6 -3 2 ppm for young sites (< 3 years following logging) and 19 ppm for a 110 year old site (Gordon and Van Cleve, 1983). Fyles et al. (1990) determined forest floor potential mineralizable N values between 152 - 847 ppm in the dry, maritime Coastal Western Hemlock biogeoclimatic zone; half o f our values fall within this range, though the remainder o f our values are higher. Results fi'om studies in a Mountain Hemlock forest in Oregon (Matson and Boone, 1984) have shown results o f 91 ppm (<10 years), 54 ppm (18 - 50 years), 35 ppm (65 - 90 years) and 32 ppm (>200 years) for the forest floor horizons and 1.2 ppm (< 10 years), 1.5 ppm (1 8 -5 0 years), 0.9 ppm (65 - 90 years) and 0.4 ppm (>200 years) for the mineral horizons which are all greatly below our results. It is important to note that the laboratory procedure we used (Powers, 1980) represents potential mineralization and may not reflect field availability. Mineralization may be overestimated because the sample preparation process includes the removal o f carbon in the form o f plant materials larger than 2 mm diameter, the C/N ratio is decreased thereby increasing the activities of soil microorganisms (Zak et al., 1986). The breakdown of data into age classes (Table 5 .17) indicate significant differences between the ranked means o f the L, H and B horizons. In each of these cases, the Mid-Seral and Late Serai age classes are not significantly different fi'om each other. The Early Serai age class is grouped with the Late Serai in the B horizon but not in the H horizon. As with the L horizon in the N H / analysis, the H-Test notes statistically significant differences, while Fisher’s LSD test does not. As indicated previously, this discrepancy is ignored and no significant difference is assumed (B. Zumbo, personal communication, 1997). -98- Table 5.17 Hajrizon Minimum, maximum, mean and standard deviations o f mineralizable N contents ppm) by horizon and age c ass. AgeCW# a WUbàmm Mean Standard Deviation iiMÜüiNi Early Serai L* _ _ f 6 2 _____ Mid-Seral ________ 1080 574 , 2040 434 1 1640 249 h - - - 1040 407 - Late Serai F H* A 465 Early Serai 5 I 378 ! 966 ! 610 ! 246 Nfid-Seral 11 , 616 1 1710 , 1214 I 371 Late Serai 7 1 560 1 1230 1 906 . 275 Early Serai 10 1 308 ! 1150 ! 550 ! 261 ^ — « Mid-Seral 11 I 616 , 1390 1 1020 I 283 Late Serai 11 1 476 1 1860 , 1060 , 495 Early Serai 16 ! 16.8 53.2 ! 28 1 Mid-Serai 20 ^a Late Serai Early Serai 1 ^^a a^a w aa ^Laa 16 I 16 I ^^a ^^a ^^a M aa sL m b w Mid-Seral 20 , ^a ^^a ^^a a^a 19.6 ^^a ^^a 1 1 I 25.2 ! a^a ^^a ava ^km a 1 « M a ^^a sM , ^^a ^m a 47.6 I 64.4 ! ^^a ^^a ^^a 61.6 I 84 37 — , 27 , 45 ! 44 ■ 8.6 11 ^^a ^aa ^aa a^a . I ^^a M M mm aaa ^^^a m m I ^aa a ^^a ^^a s —aa» 31 31 11 ^sa I ^^a ^^a aas ^aa ^^a a^a ^^a ^^a M S Late Serai 16 11.2 * = H-Tests showed significant differences between the age classes. I 146 a^^a w 16.8 14 b ^s , 12 sm m m « 24 The mineralizable N tests are vital as t h ^ are believed to represent a significant nitrogen pool within the ecosystems (Fyles et al., 1990). The anaerobic method used approximates the potential minerahzation o f nitrogen over a six-month period in the field (Powers, 1980). While it has been noted that nutrient cycling within ecosystems may change with succession (MacLean et a i, 1983), relatively small changes should be seen in nitrogen mineralization in forest floors during secondary succession after disturbances like fire (versus logging) (Vitousek et aL, 1989). Our results in the L and H layers, from stands originating after fire, tend to follow their trend. The Kruskal-Wallis H- -99- Tests found significant differences in the ranked means for both o f these horizons, though not for the F horizon. Examination o f the descriptive data indicates that the Early Serai mineralizable N levels are significantly lower than the Mid-Seral and Late Serai age classes. The L horizon values are 676 ppm in the Early Serai age class and 1040 ppm and 938 ppm in the Mid-Seral and Late Serai classes, respectively. Similarly, in the H horizons, the Early Serai mean is almost doubled fi’om 550 ppm to 1020 ppm in the Mid-Seral age class and 1060 ppm in the Late Serai. The interaction effect between the different horizons and the age classes shown in the GLM (Table 5.13) indicates that there is another variable affecting the mineralizable N levels. As with above, further analysis would be required to determine the cause. The high levels obtained for mineralizable N may be attributed to the low soil temperatures determined for all o f the study sites. Mean annual soil temperatures under 10°C have been found to limit nutrient mineralization at the forest limit in the interior o f Alaska (Sveinbjomsson et al., 1995) and in the Scottish Ifighlands (Morecroft et at., 1992). The annual soil temperatures reported in our study are lower than 10°C. It appears that low soil temperatures may be slowing the decomposition of the organic litter and, therefore, maintaining the unusually high mineralizable N levels (MacLean e ta l, 1983; Reich ef a/., 1997). 5.3.3.1 M ineralizable N and Site Quality Mineralizable nitrogen has been used as an index o f forest site productivity (Klinka et aL, 1994). The humus form acts as an expression o f soil biological activity and the nature o f the forest floor may be viewed as an indicator o f decomposition and the potential release o f available nutrients (Courtin et a i, 1988). Fyles et al. (1990) have indicated that forest floors o f similar morphology - 100 - should show similar nitrogen mineralization characteristics. While the range is larger for our H horizons, the mean and median are higher for the F horizons (Table 5.18) indicating an overall higher level of potentially available nitrogen within the F horizons o f the study sites. This result mirrors the amount o f F and H materials found within the pedons studied. Though not all pedons had F and H horizons (10 pedons contain an F horizon and 10 pedons contained H horizons), total depths o f these two horizons were nearly equal when compared. Table 5.18 Comparison o f minera izabie N results between the F and E horizons. Horizon M in. (ppm) M ax. (ppm) M ean^ppm) M edian (ppm) F 378 1708 989 966 H 308 1862 889 847 Klinka et al. (1994) have suggested that mineralizable nitrogen levels within the top 30 cm o f the mineral soil may be used as an estimate o f the nutrient conditions in montane boreal forests. Each o f the sites has been classified (Table 5.19) using the procedure proposed by Klinka et al. (1994) for the characterization o f the quality o f the nutrient regimes based on mineralizable N levels in the mineral horizons (<2 ppm = very poor, 2-8.9 ppm = poor, 9-27.4 ppm = medium, 27.5-110 ppm = rich, and >110 ppm = very rich). A weighted average based on the determined depths of the A and B composite samples is being used as an approximate representation o f the top 30 cm of the mineral soil (K. Klinka, personal communication, 1996). Each of the age classes are within the lower range of the rich soil nutrient regime classification (Early Serai mean = 34.6 ppm, Mid-Seral mean = 34.2 ppm. Late Serai mean = 34.1 ppm). However, when compared on a site by site basis, sites 3, 4, and 11 are within the medium soil nutrient regime while the 10 other sites remain within - 101 - the rich soil nutrient regime. Klinka et aL (1994) found the majority o f their sites to be in the medium and poor categories, though they conducted their study in drier and warmer subzones (their SBSdk and SBSmc versus our SBSvk) of the Sub-boreal Spruce biogeoclimatic zone. As well, their studies were conducted primarily on Luvisols and less frequently on Podzols or Brunisols, whereas, the majority o f our pedons are Orthic Humo-Ferric Podzols and Eluviated Dystric Brunisols while only two are Luvisols. However, their findings for the very moist sites ranged from medium to very rich which was closer to our findings in a very wet SBS subzone. Table 5.19 Mean mineralizable N per site as a weighted composite of the A and B horizon results. Site Cfau»ifiaition Mean AKmermlmmhle N (ppm) Soil Mntrient Regime 1 E.DYB 41.1 rich 2 O.HFP 30.1 rich 3 E.DYB 23.8 medium 4 E.DYB 25.2 medium 5 O.GL 38.2 rich 6 GLE.DYB 30.1 rich 7 O.HFP 45.1 rich 8 O.HFP 50.7 rich 9 O.HFP 40.5 rich 10 GLE.DYB 32.7 rich 11 E.DYB 27.4 medium 12 E.DYB 30.2 rich 13 O.HFP 29.4 rich 102 - When the weighted average mineralizable N levels (Table 5.19) are examined with respect to the soil classifications, the pedons classified as Orthic Humo-Ferric Podzols are shown to have three of the top four weighted mean values. Pedons 7, 8 and 9 all have values above 40 ppm, yet all three come from different age classes. It is possible that the translocation o f amorphous organic m atter in the podzolization process and high levels o f precipitation in our study area may be responsible for this trend, though this is only conjecture and requires fiirther study. As the organic matter moves downward through the sandy soils, nitrogen immobilized in the humus may not be released, thus leading to increased mineralizable N levels. This is contrary to the findings o f Reich et al. (1997) who indicated that Luvisols should have higher mineralizable N levels due to their better water-holding capacity and higher base saturation levels. However, they felt that water shortage was limiting in their Brunisols which probably is not the case in the SBSvk. In fact, the opposite may be true in our study region as water saturation o f the soil during the spring thaw is more likely to be a problem in clayey soils which drain more slowly than sandy soils. 5.3.4 C/N Ratio The C/N ratio is used as an indicator o f the propensity o f nitrogen to be mobilized with the tendency increasing as the ratio decreases (Viro, 1974). In our study, the mean C/N ratio values for the forest floor horizons range from 19.2 to 43.3 and from 14.5 to 39.6 for the mineral horizons. Our mean values have a larger range than those reported by Klinka et al. (1994) who reported C/N ratios from 27 to 40 in the forest floor and 19 to 20 in mineral horizons o f other subzones o f the SBS, though their sites (SBSdk and SBSmc) are drier than ours occurring on the Interior Plateau rather than in mountainous terrain. However, our results are similar to those o f Kimmins and Hawkes -103- (1978) who reported a mean value o f 23.2 for their forest floor samples and means o f 9.9 and 20.9 for their Ae and B fl horizons, respectively, in the SBSwk subzone northeast o f Prince George. O ur C/N values are substantially lower than those o f the decaying wood dominated forest floor sites in the Coastal Western Hemlock (CWH) biogeoclimatic zone studied by Fyles et aL (1991b) in which they obtained ratios between 215 and 344. One should note that Fyles et al. (1991b) assumed a 50% C content whereas our C content ranged fi-om 28% to 47%. However, it is not unusual for SBS subzones in the interior o f British Columbia to have lower C/N ratio values as these areas are drier (mean annual precipitation for SBS zone ranges fi'om 440 - 900 mm) than the CWH (mean annual precipitation ranges firom 1000 - 4400 mm) regions (Pojar et aL, 1991; Meidinger e ta l., 1991). The mineral horizon values are slightly higher than those obtained by Fisk and Schmidt (1995) in their Carex tundra communities in the Front Range o f the Colorado Rockies (mean C/N Ratio values o f 12.1 - 13.0). Theoretically, the higher ratios in our region compared to those presented in the other studies above are to be expected as the cooler temperatures o f our study area lead to slower rates o f decomposition (Brady, 1990). The results o f our C/N ratio analysis are provided in Table 5.20. Only the B horizon shows a significant difference in the C/N ratio. In the B horizon, the Mid-Seral and Late Serai age classes are grouped separately firom the Early Serai age class based on Fisher’s LSD. Since the C/N ratio is considered to be somewhat constant (the length o f time for recovery following the addition o f new materials being determined by the C/N ratios of the substances added) within ecosystems, it is expected that no significant differences will be observed (Brady, 1990). Macadam (1987) found that C/N ratios returned to prefire levels within 21 months o f broadcast slash burning in the SBS zone which is a shorter period o f time than had occurred prior to the sampling o f our youngest site (Site -104- 13 at 3 years post-fire). Table 5.20 Horizon Minimum, maximum, mean and standard deviations of C/N ratio by horizon AgeCbmm Minimum ft M caft Early Serai L Early Serai H A 52.1 14.5 4 35 e ! 99.3 ! ^ 5 ! 18.1 ^ g W : : 3.64 35.7 ! 35.6 MW Mid-Seral 11 1 16.9 I 25.3 I 21.8 , 2.73 Late Serai 7 , 21 I 28.4 1 25.1 , 2.82 Early Serai 10 ! 53.6 ! 25.5 ! 11 I 25.6 1 21.6 , Late Serai 11 1 19 24.6 I Early Serai 16 ! 4.05 30 ! Mid-Seral Mid-Seral ^M ^ w WM 16.9 ! 17.4 I ^ w WW WM ^ w ^wa ww a^^w I 29 1 ! 169 MW 11.4 1 ol^M wm w Lw WW ^ w 20 1 W» aa^ ^^^M MW i^w ^W J^M mw ww ww 64.9 1 24.6 503.2 , 38 I ^wa I 7.93 , Early Serai 16 I 9.61 I Mid-Seral 20 , 8.04 I 29.5 Late Serai 16 , 10.9 , * = H-Tests showed significant dififerences between the age classes. 64.8 ^ w ^ w ww WW ^w — W» . MW J ^ M ^ w ww a 2.72 ww a 3.42 37.5 MW MW WM a 14.1 52.2 , 21.4 ! , 17.5 . 6.29 I 20.3 , 12.5 ^w ^w ^w ^w ■ 10.4 wm mw ww 16 ww a^^w WM ^ w ^ w ww I WM ^ w <^W ^W «^^M Late Serai B* 11.7 Mid-Seral Late Serai F Standard Deviation a 121 5.68 ww wm «^m ^ w a Net immobilization o f nitrogen has been determined to occur in forest floors with C/N ratio values above 25 and total N values below 1.8% (Haynes, 1986b). The mean values of five of our sites fall within these ranges; sites 2, 5, 9, 10, 12 (see Table 5.11). The remainder have C/N ratio values below 25. No trend could be determined with respect to the age class analysis. -105- 5.3.5 Nitrogen and Vegetation Coverage Nitrogen mineralization has been found to be strongly related to the species composition o f an ecosystem primarily due to the differences in the chemical quality of the plant litter (Zak et aL, 1986). Vitousek et al. (1989) suggested that available nitrogen may not be limiting to plants during primary succession since many o f these plants have non-sclerophyllous leaves (i.e. hardwoods) and may be able to obtain sufficient nitrogen from precipitation. Our findings indicate that herbs and mosses are most abundant in the Early Serai age class. Mosses are known to decompose slowly and act as a water filter and nutrient sink by absorbing precipitation efficiently (Vitousek et aL, 1989). A thick moss layer also has the ability to lower soil pH and temperature which may lead to slower organic matter decomposition and lower nutrient availability (Bissett and Parkinson, 1980; Kuuluvainen et aL, 1993). Differences in cellulose, hemicellulose and lignin composition between the coniferous needles and herbaceous understory would also lead to a different rate of decomposition over time as the slower decomposing needles gradually increased in percentage in the forest floor horizons (Vitousek et aL, 1989). As noted by Fyles et aL (1990), an understanding o f the mineralization characteristics o f the different forest floors, and indeed, the different plants providing materials for the forest floors, is required before accurate predictions o f the amount of nitrogen available to plants can be made. Expected successional effects would be a larger take-up and storage o f nutrients by the growing trees as well as a possible decrease in the leaching o f nutrients into the soil due to the concentrating of precipitation down the tree stems rather than evenly over an unprotected area. Also, the addition o f coniferous needles to the forest floor would increase the acidity and affect the composition of the litter as well as the F and H layers (Kuuluvainen et aL, 1993). It has also been -106- suggested that white spruce forests will revert to white spruce forests following moderate burning and will change to aspen, birch, poplar or spruce following single severe fires (Kelsall et a i, 1979). Repeated severe fires change the forests to herbaceous or shrubby communities (Kelsall et a i, 1979). Our Early Serai sites are dominated by herbs and shrubs, though spruce se e d lin g s have been listed in the inventory for this age class. Deciduous tree cover does not appear to play a large role in early post-fire succession in the SBSvk subzone (C. Delong, personal communication, 1997). A major source o f N H / in forest soils comes fi'om the decomposition o f amino acids, amides and proteins fi'om dead plants, animals and microorganisms (Haynes, 1986a). It appears that the increased cycling o f the growing vegetation cover may be responsible for the noted higher concentrations o f N H / over time. Table 2.2 provides a breakdown o f the available vegetation cover for Sites 1-12 by species and age class and the mean amount o f each type o f vegetation is summarized in Table 5.21. (Note: Where vegetation coverage exceeds 100% in the herb coverage, plants are overlapping.) The species averaging more than 10% coverage in the Early Serai sites Rubuspat^iflorus, Epilobium angustifolium, Gymnocarpium dryopteris and Polytrichum juniperirmm. In the Mid-Seral sites, Picea glauca x engelmannii, Oplopanax horridus, Vaccinium membranaceum and Vaccinium ovalifolium represent at least 10% mean percent coverage. The Late Serai sites species representing at least 10% coverage, include lasiocarpa, Picea glauca x engelmannii, Oplopanax horridus, D ryopteris assim ilis and Gymnocarpium dryopteris. Data reveal a steady increase in the percent coverage o f Abies lasiocarpa and Picea glauca x engelmannii fi'om the Early Serai through the Midand Late Serai age classes: fi'om the maximum o f 1% cover at one o f the sites in the Early Serai to the 60% maximum seen in the Mid-Seral and the 84% in the Late Serai. -107- Age Class Early Serai M Id-Seral Late Serai Tree Covo' % 0.4 32.4 56.8 Shml^Cinror % 52.6 83.5 75.1 Cover % 108.9 54.5 72.8 Moss Cover % 35.3 19.1 33.9 Epilobium angustifolium, a nitrophytic species representative o f nitrogen-rich soils (Klinka et al., 1989), is found predominantly in the Early Serai sites. However, other species such as Rhododendron albiflorum (indicative of nitrogen-poor sites) and Calamagrostis rubescens (indicative of medium nitrogen levels) also are found only on the Early Serai sites. Robertson et al. (1988) examined the spatial variability of nutrients (particularly nitrogen) and plant succession resulting from a natural disturbance. Their study looked at the small-scale heterogeneity of nutrient regimes as related to the pattern of early plant succession. They noted that it was unclear if the plant community reflected the nutrient levels or whether they affected them. Also, though it was originally believed that Epilobium angustifolium and Rubus idaeus occurred on recently burned sites because they required nitrogen in the NO3*form, Epilobium angustifolium has also been shown to be able to take up nitrogen as (Viro, 1974). Nevertheless, the variety o f plants inventoried within the study sites may cause the variation noted in the different nitrogen levels within the Early Serai communities (as is demonstrated with the NO3' results in Figure 5.5). Higher mean mineralizable N levels are found in the Mid-Seral and Late Serai age classes than in the Early Serai age class (Table 5.17). In his study in Quebec, Moore (1980) found that the litter from spruce trees had the ability to immobilize nitrogen. Since the sites with more spruce trees would be more likely to have spruce litter within the forest floor horizons, and since conifer needles - 108- are among the slowest o f forest floor materials to decompose (Bissett and Parkinson, 1980), this may be a factor which explains the variation in mineralizable N levels over time Also, mosses such as Pleurozium schreberi (inventoried in the Mid-Serai and Late Serai), Hylocomium splendens (only in the Late Serai) and other feather mosses have been found to act as nitrogen immobilizers (Weber and Van Cleve, 1981) and may add to the higher mineralizable M values foimd in these age classes. As weU, ericaceous shrubs such as the Vaccinium species are known for their suppression o f nitrogen mineralization (Kimmins, 1996) and V. membranaceum and V. ovalifolium were found predominantly in the Mid-Seral and Late Serai sites which may add to the explanation o f the higher levels of mineralizable N found there Arocena et al. (in preparation, 1997), using the data from this study, estimated the total mass o f the different forms of nitrogen which increased with stand age. However, the increase in content does not necessarily reflect nitrogen availability which is related to nitrogen concentration and the rate at which nutrients are released through decomposition and mineralization (Keenan et a l, 1993). Nitrophytic species indicative o f nitrogen rich sites such as Devil’s Club {Oplopanax horridus) (Klinka et a l, 1989) demonstrate the trend by showing an increase in percent coverage from an average of 0.3% in the Early Serai sites to an average o f 19% in the Mid-Seral sites and 43% per site in the Late Serai sites. It should be noted that the intensity of the fires upon which this retrospective study is based were not known, although rough estimates o f forest floor indicates a minimum o f 50% reduction in depth after wildfires. More intense fires may lead to higher soil temperatures and longer duration o f soil heating, which, in turn, can affect the length of time for mycorrhizae-dependent plants to return to the sites (Klopatek et a l, 1988). Thus, the intensity o f the forest fire may have acted as an -109- additional confounding factor affecting the species compositions observed and is another reason this study has not attempted to link specific plants to the nitrogen activity o f the sub-boreal forest. Since the purpose o f this thesis is to examine the relationships between post-fire stand age and nitrogen dynamics, the area of plant/nutrient regime interactions was not investigated and would require considerable effort to determine if any relationships exist. 5.3.6 Projection o f Nitrogen Concentrations within the MMF Nine combinations of soil complexes and forest age classes representative o f our study sites are found to overlap in significant quantities within the SBSvk biogeoclimatic subzone o f the MMF during GIS analysis; sufticient data exists to project nitrogen values for six o f these as soil samples were not collected in areas matching the remaining three soil complexes/age classes coverages. The combined area o f these six complexes represents approximately 10% o f the total area o f the model forest (Table 5.22). The projections o f nitrogen levels are provided in map form as Figure 5.6. (Note : Only the northwest section o f the model forest is presented in this map as the concentration of polygons in this region allow the most confidence in making predictions.) It is intended that the projections made herein be used in conjunction with other GIS layers in order to obtain a more complete picture o f the landscape. Use o f the GIS database in this manner may provide forest practitioners with a tool which may be included in the monitoring o f tree plantations, however, it is advised that nitrogen levels be monitored over time to confirm the ranges projected in this study. Also, caution should be used in applying these projections where forest management activities have taken place since the projections are based on succession after fire; particularly in the case o f the < 20 years age class. Should future research within the MMF find - 110 - Table 5.22 Areal coverage of nitrogen projected areas within the MMF. #of pofygons Represeoted (ba) % of MMF Averil + Dominion / Early Serai 591 3432 2 Averil + Dominion / Mid-Seral 46 111 0.1 Averil + Dominion / Late Serai 258 4909 3 Dominion + Averil / Mid-Seral 22 80 0.04 Dominion + Averil / Late Serai 307 9664 5 Bearpaw Ridge + Captain Creek / NCd-Seral 56 702 0.4 Soil Com plex / Class similar results to the projections provided herein, a more complete understanding of the nitrogen dynamics in these ecosystems will have been achieved through this research. -Ill- Figure 5.6 ProjecÜomofPnÊrogemComceoÊruÊlomg wËMmAe SBSvk Sobmooe o f A c McGregor Mo< 533986» C122«28'30"l M c G r e g o r P r o d u c e d b y th e M c C te iD r M o d e lR w tA M o c ia t a u F o r m e r e o if a n n a ic D d a o iit IIÜ I p n d u c i o r o d H T p r o d u c u p l o K p l i a n e ( 250) 962- 3S 4S o r ( 250) 962- 35* 9. 1# |; §3 1997 M c G i w v M o A i F i M A ll lig b u m o v e d . N d p o t o f U d e m e p m m y b e — n r s - r f iin r — t e p r j i i œ d w i f l k j u i 11» w i l o o i p o m i o f c n o f I b e F O R f Î 5M O D È i .£5 W & S r e g O T M o d e l F o o O M3886m n 2 2 » 2 r4 2 " | iimM Model Forest. Projection of Nitrogen Concentratioi within the SBSvk Subzone o f the McGregor Model Forest A C tC X M S i Q AMefihOominion Dominkmy^Mril Bear taw RidflerOptain O eek Study Paints H—t ** «fnitracM w I mm ta n é widria Micctad areas efime (Forest. The fiist rm#e o f vOues rqaeemo dw m iieni hohzom and die sera perendiseee) rseseeoSe the faewt floor hohmns N(W) S L S u ^ • ls-its •■n L94S :7 ^ NCH) ON IWsCPPSi) W .*(|PBi) -NtaM) NW) ON NDs'W") IM ^N dew ) * 1:125 000 - Kaomalraa m i NWJS3 ZiM 10 PISNWM Jems .13.1007 - MUM SIS a -i-u ) aa-r?) aS>X7» avMrm Projection o f Nitrogen Concentrations within the SBSvk Subzone of the McGregor Model Forest SOILASSOCtAriON ACEOASSlyni SERIES-1:SEIIIES>2) j%eril:Domtnion OominioiK/iNeril Bear taMf RidieKIiptoin Oeek Study Mnls 8 ? S V ? A 1 1Y rW # Ck. Ihn » » ■fnitrac** ttmm witWa iMccttd wnm ordM McGrcf«r MmM (Forctt. The fint r u e of vetiai rep e e m c die m iu n l hanm m aid the second sec of vskiee (in perenchesee) ruprseade the finest floorhoiiaw MtH) NOs(*e:) NCH) ON NOs(##") Mk.N(#ta) N(%) ON ( ® s-(|P » ) ■•►NCppas) a-i-aj) a«-r> Od-Sl« os-m Chapter 6 - SUMMARY AND CONCLUSIONS In the Central Interior o f British Columbia, specific knowledge o f the types o f soils and their properties is scarce. This deficiency imposes limitations on the short and long term planning for sustainable forest management. Since the end o f the last ice age, the Fraser Glaciation, lightningcaused fires have been a major force in determining the structure o f the landscape. With fire return intervals in the Sub-boreal Spruce biogeoclimatic zone ranging between 75 and 250 years, an understanding o f how they affect nutrient cycling, particularly nitrogen contents, is vital in order to ensure to sustainability of modem forest harv'esting practices. This thesis was conducted within the McGregor Model Forest with the objective o f providing additional benchmark information on the types and nitrogen content o f soils in selected post-fire sites in the SBSvk subzone. Classification o f 15 pedons at 13 study sites reveals the presence o f five Eluviated Dystric Bmnisols, two Gleyed Eluviated Dystric Brunisols, five Orthic Humo-Ferric Podzols, two Orthic Gray Luvisols and one Rego Humic Gleysol. Podzolization seems to be the dominant pedogenic process in the area along with clay movement (lessivage) and minor hydromorphic processes. Four o f the Eluviated Dystric Brunisols - Pedons 1,3,4 and 11 (upper slope) - are believed to be the result o f incipient podzolization and, with time, are expected to develop into Orthic Humo-Ferric Podzols. The sandy parent materials, cool temperatures and high precipitation rates provide a mechanism conducive to the translocation o f organic acids with or without Fe and A1 into the B horizon. Lessivage is the dominant process in the two Orthic Gray Luvisols - Pedons 5 and 11 (upper slope) and is shown to be in the early stages in Pedon 12. The fifth Eluviated Dystric Brunisol - Pedon 12 should develop into an Orthic Gray Luvisol as it has been formed on different parent material than -113- the other Brunisols. Hydromorphic processes result in the formation o f Gleysols and gleyed features - Pedons 6, 10 and 11 (lower slope). These three gleyed pedons resulted from changes in microtopography. The Rego Humic Gleysol, in particular, was formed on colluvium at the base o f a relict avalanche which was responsible for the poor drainage and high level o f organic matter found. The 13 sites were categorized into three age classes based on the length of time which had passed since the last forest fire: Early Serai (four sites < 14 years post-fire), Mid-Seral (five sites 50 - 80 years post-fire) and Late Serai (four sites > 140 years post-fire). Total N results compared well to other studies which have been carried out in or near the MMF. No significant differences were found in Total N among the different serai classes indicating that any post-fire effects were no longer present after 14 years. Available N O / levels were found to be higher in the Early Serai age class compared to the Mid-Seral and Late Serai age classes. Available N H / levels were highest in the Mid-Seral age class for the forest floor and highest in the Late Serai age class for the mineral soil, but were consistently lowest in the Early Serai age class. Mineralizable N values were significantly lower in the Early Serai age class compared to the Mid-Seral and Late Serai age classes. Significant differences in mineralizable N, available N O / and available NH,"^ levels over time indicated that nitrogen availability changes with stand succession after fire within the SBSvk subzone o f the MMF. It was suspected that changes in vegetation species was the dominant factor controlling the nitrogen levels since it controls the chemical and physical characteristics o f the organic matter deposited to the forest floor and controls what chemicals are subsequently leached into the mineral horizons. It could not be proven that vegetation establishment and development were the result o f variations in nitrogen status, or if the opposite were true (i.e. the vegetation caused the variability found in the -114- nitrogen levels) or, in fact, if both were true. The relationship between specific types o f vegetation and the levels o f the various types o f soil nitrogen needs further research if a model for field assessment o f ecosystem nitrogen status is to be produced. A GIS was used to integrate the nitrogen results from this study with soil survey and forest age class coverages. Superimposing the two coverages allows the research conducted within this study to be placed in a larger spatial context than at the point level in which the data was collected. When used in conjunction with other GIS-based forest management data, these nitrogen projections should provide insight to help guide friture forest management decisions. However, the predicted nitrogen levels should be verified by frirther soil analysis because o f the natural spatial heterogeneity o f soils. 6.1 Fcrest M anagement Im plications There are three main aspects o f this thesis which can benefit forest management in the SBSvk. Firstly, the soil classification and its link to the available soil survey data provided baseline information on the types o f soils found in the region, as well as their physical, chemical and morphological properties. This thesis also confirmed that the pedons classified were among the possible soil types listed within the soil survey reports. Properties such as the soil texture (percent content o f sand or clay, in particular) are useful in rights-of-way planning and slope stability analyses. Secondly, the use o f a GIS in projecting nutrient values demonstrates the ability o f forest practitioners to increase the number o f possible scenarios when conducting short and long term p lanning. For example, this study projected possible levels o f nitrogen in selected forest areas o f different ages. Finally, more data has been determined for the nutrient status o f soils in the SBSvk. -115- When considering planting seedlings following wildfire, adjustments can be made to the choice o f tree species and fertilizers to be used based on the species’ particular nitrogen requirements. 6.2 Recom m endations This study has found shortcomings in the availability and completeness o f soil information within this region. The following are some suggested areas where further research would be beneficial. 1. Since the levels o f mineralizable nitrogen are much higher in this biogeoclimatic subzone than other areas o f British Columbia (and indeed other areas o f the SBS) knowledge o f the rate o f nitrogen cycling within the ecosystem would further add to the understanding o f nutrient cycling, in general. Also, examination o f the effects o f climate change on this potentially large nitrogen pool could provide insight into the possible nutrient status o f the future o f the SBSvk. 2. In order to address the problems associated with the limitations o f single measurements o f very labile nutrients (i.e. NO3*and ), long-term plots should be established from which chemical changes may be monitored over time. As well, these long-term plots will provide information useful to the understanding o f nutrient dynamics in the SBSvk. 3. Vegetation/soil nitrogen relationships within the SBS should be studied in depth. By better understanding the nitrogen pathways through a plant’s life cycle, it would be easier to determine site productivity and nutrient status from field-based vegetation inventories. 4. An analysis o f the variations in vegetative succession (species compositions over time) in the SBS following different types o f forest disturbances (i.e. fire or harvesting) would allow for -116- better predictions o f the status o f soil nitrogen, etc. as vegetation is the primary source o f nutrient input. 5. Ground truthing o f the GIS projections o f the different nitrogen levels presented in this thesis would provide confirmation o f the validity o f its use. As well, an assessment o f the same procedure in predicting the levels o f other nutrient levels (i.e. exchangeable cations and other nutrients required by plants) in the study areas. -117- LITERATURE CITED Agee, James K. 1993. Environmental effects o f fire, /n Fire Ecology o f Pacific Northwest Forests. Island Press: Washington, D C. 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QuaL Res. 33: 231-240. -130- APPENDIX B Profile Descriptions, Diagnostic Horizons and/or Properties and Classification o f Pedons 2 ,3 ,4 , 6, 7 ,8 , 10, 11 (upper slope), 11 (middle slope), 12, 13 -131- Pedon 2 - Profile Description. Horizon Death fcm) S DcscriDtioB Bryophytes. Ln 9-7 Deciduous leaves, coniferous needles, twigs, fungal mycelia. Fm 7-1 Moist; very dusky red (2.5YR 2.5/2 m); weak, compact matted, loose, acerose; few, fine roots; few, clustered fungal mycelia. Hr 1-0 Moist; (5YR 2.5/2 m); strong, granular, loose, gritty; common, fine roots; few,. random droppings; common, random fimgal mycelia. Ae 0-19 Gray (7.5YR 5/1 m); loamy sand; single grain; loose; plentiful, very coarse, vertical, exped roots; charcoal fragments; clear, smooth boundary. Bfl 19-32 Brown (7.5YR 4/4 m); silty sand; moderate, fine to medium, subangular bloclQ'; friable; gradual, smooth boundary. BG 32-50 Dark brown (7.5YR 3/3 m); loamy sand; moderate, fine to medium, subangular blocky; friable; gradual, smooth boundary. BC 50-61 Dark brown (lOYR 3/3 m); loamy sand; moderate, fine to medium, subangular blocky; finable; clear, smooth boundary. C 61+ Olive brown (2.5Y 4/3 m); sand; massive; firm. Classification, Diagnostic Horizons and/or Properties Canadian System: Podzolic B horizon. Bf at least 10 cm thick. Organic C = 0.5-5% FCp+AIp = 0.6% or more. Orthic Humo-Ferric Podzol. U.S. Soil Taxonomy: Epipedon: Ochric Subsurface horizons: Albic, Spodic. Subsurface materials: Albic, Spodic. Typic Haplocryod. -132- Pedon 3 - Profile Inscription, Horizon D w th fcm ) Ln 6-4 Deciduous leaves, coniferous needles, bryophytes, twigs, fungal mycelia. Fm 4-2 Moist; (black (lOYR 2/1 m); moderate, compact matted, friable, mushy; few, fine roots; common, random fungal mycelia. Hh 2-0 Moist; black (lOYR 2/1 m); strong, compact matted, friable, mushy; common, very fine roots; abundant, random fungal mycelia. Ae 0-10 Dark gray ( lOYR 4/1 m); loamy sand; moderate, medium, subangular bloclqr breaking into single grain; friable; abundant, medium to coarse, vertical, exped roots; clear, smooth boundary. BQl 10-24 Dark yellowish brown (lOYR 4/6 m); loamy sand; moderate to strong, fine, subangular blocky breaking into single grain; friable; plentiful, medium to coarse, vertical, exped roots; clear, smooth boundary. BQ2 24-34 Dark yellowish brown (lOYR 3/4 m); sand; single grain; loose; few, fine to medium, vertical, exped roots; gradual, smooth boundary. BC 34-46 Olive brown (2.5Y 4/4 m); sand; single grain; loose; very few, fine to medium, vertical, exped roots; gradual, snwoth boundary. C 46+ Dark yellowish brown (lOYR 3/4 m); single grain; loose; very few, vertical, exped roots. Classification, Diagnostic Horizons and/or Properties. Canadian System: Bfj horizon. pH < 5.5 by 0.0 IM CaCL. Eluvial horizon at least 2 cm thick. Eluviated D ystric B m nisol. U.S. Soil Taxonomy: Epipedon: Ochric Subsurface horizons: Albic. Subsurface materials: Albic, Cambic. Typic Cryochrept. -133- Pedon 4 - Profile Description. Horizon Denth fcm) S DcscriotioB Bryophytes. Ln 5-4 Deciduous leaves, twigs, coniferous needles. Fa 4-1 Moist; very dark brown (7.5YR 2.5/2 m); moderate non-compact matted, loose, fibrous; abundant, fine roots; few Collembola; few, random fungal mycelia. Hh I-O Moist; very dark brown (I0YR2/2 m); strong, granular, friable, gritty; abundant, very fine roots; few Lumbricida, few Collembola', few, random droppings; few, random fungal mycelia. Ae 0-6 Gray (7.5YR 6/1 m); silt loam; moderate to strong, fine to medium, subangular blocky; slightly finable; abundant, medium and coarse, horizontal, exped roots; charcoal fiagments between LFH and Ae; presence of weathering rock fiagments (~ 2-50 mm in diameter) with Fe oxides; clear, wavy boundary. Bml 6-22 Strong brown (7.5YR 4/6 m); clay loam; moderate, fine to medium, subangular blocky; finable; plentiful, fine and medium, random, exped roots; gradual, smooth boundary. Bm2 22-42 Dark brown (7.5YR 3/3 m); clay loam; moderate, medium, subangular blocky; finable; plentiful, medium, horizontal, exped roots; gradual, smooth boundary. BC 42-58 Brownish yellow (lOYR 6/8 m); clay loam; moderate, medium to coarse, subangular blocky; firm; few, fine to medium, vertical, exped roots; gradual, smooth boundary. C 58+ Yellowish brown (lOYR 5/6 m); clay loam; massive; very few, fine to medium, vertical, exped roots; abundant weathering of rocks with Fe oxides. Classification, Diagnostic Horizons and/or Properties Canadian System: Bm horizon. pH <5.5 by O.OIMCaCL. Eluvial horizon at least 2 cm thick. Eluviated Dystric Bm nisol. U.S. Soil Taxonomy: Epipedon: Ochric Subsurface horizons: Albic, Spodic. Subsurface materials: Albic, Spodic. Typic H aplocryod -134- Pedon 6 - Profile Description. Horizon Denth fcm) S Dcscrintion Bryophytes. Ln 4-3 Deciduous leaves, twigs. Fm 3-0 Moist; black (lOYR 2/1 m); weak, compact matted, friable, frbrous; common, very fine roots, common, random fungal mycelia. Ae 0-20 Gray (lOYR 6/1 m); sandy loam; moderate, fine to coarse, granular; friable; abundant, medium to coarse, random, exped roots; clear, wavy boundary. Btjg 20-45 Dark brown (7.5YR 3/3 m); loam; few, medium, distinct, strong brown (7.5YR 5/8 m) mottles; moderate to strong, medium, subangular blodqr; slightly friable; plentiful, medium, vertical, exped roots; gradual, wavy boundary. Cg 45 Light olive brown (2.5 Y 5/4 m); sandy loam; few, medium, distinct, strong brown (7.5 YR 4/6 m) mottles; massive; slightly friable; very few, fine to medium, vertical, exped roots. Classification, Diagnostic Horizons and/or Properties G leyed Eluviated Dystric Bm nisol. Canadian System: Btjg horizon at least 5 cm thick. Ae horizon at least 2 cm thick. pH < 5.5 by 0.0 IM CaCl; in upper 25 cm o f B horizon. Mottles. U.S. Soil Taxonomy: Epipedon: Ochric Subsurface horizons: Albic, Spodic. Subsurface materials: Albic, Spodic. Typic Cryaquod. O ther Site Characteristics: Aquic conditions. Redoximorphic features. -135- Pedon 7 - Profile Description. Horizon Descrintkm Denth fcm) S Bryophytes. Lv 3-2 Twigs, coniferous needles, fungal mycelia. Hr 2-0 Moist; very dark brown (lOYR 2/2 m); weak, massive, friable, fibrous; common, very fine roots; few Collembola', few, random fungal mycelia. Ae 0-17 Grayish brown (lOYR 5/2 w); loamy sand; weak, medium, subangular blocky breaking into single grain; non-sticky, non-plastic; abundant, fine to medium, vertical, exped roots; clear, smooth boundary. Bf 17-36 Dark brown (7.5YR 3/3 m); loamy sand; moderate, fine to medium, subangular blocky; friable; plentifril, medium, vertical, exped roots; gradual, smooth boundary. IC 36-65 Dark yellowish brown (lOYR 3/4 m); loamy sand; massive; friable; very few, medium, vertical, exped roots. lie 65+ Gravel deposit Classification, Diagnostic Horizons and/or Properties Canadian System: Podzolic B f horizon. Organic C = 0.5-5% FCp+Aip = 0.6% or more. Base saturation < 50% Orthic Humo-Ferric Podzol. U.S. Soil Taxonomy: Epipedon: Ochric Subsurface horizons: Albic, Spodic. Subsurface materials: Albic, Spodic. Typic Haplocryod. -136- Pedon 8 - Profile Description. Horizon Denth fcm) Lv 8-5 Coniferous needles, twigs, coniferous cones, fungal mycelia. Fa 5-4 M oist; dark reddish brown (5YR 2.5/2 m); moderate, non­ compact matted, friable, fibrous; few, fine roots; few Coleoptera; few, random fungal m ycelia. Hh 4-0 M oist; very dark brown (7.5YR 2.5/2 m); weak, granular, firm, gritty; common, very fine roots; few Lumbricida; common, random droppings; few, random fungal mycelia. Ae 0-18 Gray (7.5YR 6/1 m); sandy loam; m oderate, medium, subangular blocky; very fiiable; abundant, coarse to medium, vertical and abundant, coarse, horizontal and vertical, exped roots; clear, smooth boundary. Bf 18-48 Dark brown (7.5YR 3/4 m); loam; m oderate, fine to medium, subangular blocky; fiiable; abundant, medium, random, exped roots; gradual, smooth boundary. BC 48-56 Dark yellowish brown (lOYR 3/6 m); sandy loam; moderate, medium, subangular blocky; slightly friable; plentiful, fine, medium, vertical, exped roots; clear, sm ooth boundary. C 56+ Brown (7.5YR 5/4 m); silty clay loam; massive; firm; very few, fine, vertical, exped roots. Dcscrintion Classification, Diagnostic Horizons and/or Properties Canadian System: Podzolic B f horizon. Organic C = 0.5-5% FCp+Alp = 0.6% or more. Base saturation < 50% Orthic Humo-Ferric Podzol. U.S. Soil Taxonomy: Epipedon: Ochric Subsurface horizons: Albic, Spodic. Subsurface materials: Albic, Spodic. Typic Haplocryod. -137- Pedon 10 - Profile Description. Horizon Denth fcm) Lv 6-3 Coniferous needles, twigs, deciduous leaves, spruce cones. Fm 3-1 M oist; very dark brown (7.5YR 2.5/2 m); moderate, compact matted, friable, fibrous; common, very fine roots; few, random fimgal mycelia. Hh 1-0 M oist; very dark brown (lOYR 2/2 m); moderate, compact matted, finable, greasy; common, very fine roots; few, random fimgal mycelia. Ae 0-8 Grayish brown (lOYR 5/2 m); silt loam; weak to moderate, medium, subangular blocky; slightly finable; plentiful, medium, vertical, exped roots; charcoal fragments; gradual, wavy boundary. AB (dis­ continuous) 8-13 Brown (lOYR 5/3 m); silty clay loam; strong, medium, subangular blocky; finable; plentiful, medium to coarse, vertical, exped roots; gradual, smooth boundary. Bfj 13-34 Dark yellowish brown (lOYR 3/4 m); silty clay loam; moderate, medium, subangular blocky; finable; plentiful, medium and coarse, vertical, exped roots; clear, smooth boundary. Cg 34+ Olive brown (2.5Y 4/4 m); silt loam; few, medium to coarse, distinct, dark reddish brown (5YR 3/4 m) mottles; massive; slightly finable. Descrintion -138- Classification, Diagnostic Horizons and/or Properties. C anadian System: Gleyed Eluviated Dystric Bm nisol. BQ horizon. pH < 5.5 by O.OIM CaCI, in B horizon. Ae horizon at least 2 cm thick. Mottles. U S. Soil Taxonom y: Oxyaquic Cryochrept. Epipedon: Ochric Subsurface horizons: Albic, Cambic. Subsurface materials: Albic. O th e r Site Characteristics: Aquic conditions. Redoximorphic features. -139- Pedon 11 (upper slope) - Profile Description. Horizon Depth (cm) Ln 4-2 Deciduous leaves, coniferous needles, fungal mycelia. Fa 2-0 Moist; dark reddish brown (5YR 2.5/2); moderate, non-compact matted, firm, fibrous; abundant, very fine roots; common, banded fimgal mycelia. Ae 0-2 Gray (2.5Y 6/1 m); silt loam; strong, fine, subangular blocky; friable; few, fine and medium, random, exped roots; abrupt, sm ooth boundary; 1-3 cm thick. Bt 2-16 Strong brown (7.5 YR 4/6 m); silt loam; strong, fine, subangular blocky; fiiable; few very fine and coarse; random, exped roots; gradual, smooth boundary; 8 -1 8 cm thick. BC 16-27 Brown (10 YR 5/3 m); silty clay loam; strong, fine, subangular blocky; fiiable; few very fine and coarse, random, exped roots; gradual, smooth boundary; 7-13 cm thick. C 27+ Brown (lOYR 4/3 m); silt loam; m oderate, medium, subangular blocky; firm; few, very fine, random, exped roots. Canadian System: Bt and eluvial horizons. Chroma < 3 in Ae horizon. Descriptkm O rthic Gray Luvisol. Typic Haplocryod. U.S. Soil Taxonomy: Epipedon: Ochric Subsurface horizons: Albic, Argillic, Cambic, Spodic. Subsurface materials: Albic, Spodic. -140- Horizon Pedon 11 (middle slope) - Profile Description, niMihUfiio Denthfcm) Ln 6-4 Deciduous leaves, coniferous needles, spruce cones, fungal mycelia, droppings, Arachnida. Fa 4-0 Moist; very dark brown (7.5YR 2.5/3 m); moderate, non­ compact matted, friable, leafy; abundant, very fine roots; few Arachnida; common, random droppings; common, random fungal mycelia. Ae 0-26 Light gray (5YR 7/1 m); silt loam; strong, fine, subangular blocky; loose; few, fine, horizontal, inped roots; clear, irregular boundary; 12-26 cm thick. BQ l 26-41 Dark yellowish brown (lOYR 3/4 m); silt loam; weak, fine, subangular blocky; friable; plentiful, very fine, horizontal, inped roots; clear, smooth boundary; 13-15 cm thick. Bfj2 41-56 Yellowish red (5YR 4/6 m); silt loam; weak, fine, subangular blocky; very friable; few, fine, oblique, inped roots; clear, smooth boundary; 10-15 cm thick. BC 56-75 Dark yellowish brown (lOYR 4/6 m); silt loam; m oderate, fine, subangular blocky; friable; few, fine, horizontal, inped toots; clear, smooth boundary; 17-19 cm thick. n e (dis­ continuous) 75-81 Olive brown (2.5Y 4/4 m); silty clay loam; moderate, very fine, granular; very friable; very few, fine, random, inped roots; clear, smooth boundary; 0-8 cm thick. IC 81+ Strong brown (7.5YR 4/6 m); loam; strong, fine, angular blocky; loose; very few, fine, random, exped roots. 141- Classification, Diagnostic Horizons and/or Properties. Canadian System: Bf) horizon. pH < 5.5 by O.OIM CaClj in B horizon. Ae horizon at least 2 cm thick. Eluviated Dystric Brunisol. U.S. Soil Taxonomy: Epipedon: Ochric Subsurface horizons: Albic, Spodic. Subsurface materials: Albic, Spodic. Typic Haplocryod, -142- Pedon 12 - Profile Description. Horizon Denth (cm) Dcscrintioa Bryophytes. S Ln 3-2 Coniferous needles, deciduous leaves, fungal mycelia, Arachnida. Fm 2-0 Moist; dark brown (7.5 YR 3/3 m); strong, non-compact matted, friable, acerose; few, fine roots; few Arachnida; abundant, random fungal mycelia. Ae 0-14 Pinkish gray (7.5YR 6/2 m); silt loam; moderate to strong, fine, subangular blocky; fiiable; plentiful, fine, horizontal, inped roots; clear, wavy boundary. BQ 14-48 Dark red (2.5YR 4/6 m); loam; moderate to strong, fine, subangular blocky; very fiiable; plentiful, fine, random, inped roots; clear, wavy boundary. C 48+ Dark brown (7.5YR 3/3 m); loam; strong, fine, subangular blocky; loose; few, very fine, oblique, exped roots. Classification, Diagnostic Horizons and/or Properties Canadian System: Bfi horizon at least 5 cm thick.. pH < 5.5 by O.OIM CaCl, in B horizon. Ae horizon at least 2 cm thick. Eluviated Dystric Brunisol. U.S. Soil Taxonomy: Epipedon: Ochric Subsurface horizons: Albic, Spodic. Subsurface materials: Albic, Spodic. Typic Haplocryod. -143- Pedon 13 - Profile Description. Horizon Depth (cm) Description Bryophytes and lichen. S Ln 14-11 Deciduous leaves, twigs, mycorrhizae, grasses. Fa 11-7 Vfoist; black (lOYR 2/1); moderate, non-compact matted, friable, mushy; plentiful, very fine roots; few, random droppings; few, random fungal mycelia. Hh 7-0 Moist; black (lOYR 2/1); weak, compact matted, friable, mushy; abundant, very fine roots; few, random fimgal mycelia. Ahe 0-16 Dark yellowish brown (10YR4/4 m); silt loam; moderate, fine, subangular bloclq:; very friable; common, very fine, random, inped and exped roots; clear, wavy boundary; 16-25 cm thick. AB 16-34 Dark yellowish brown (lOYR 3/4 m); silt loam; moderate to strong, fine, subangular blocky; friable; few, medium, random, exped roots; clear, wavy boundary; 12-18 cm thick. Bf 34-59 Brown (7.5YR 4/4 m); loam; weak, medium, subangular blocky; firm; few, coarse, oblique, exped roots; clear, wavy boundary; 15-27 cm thick. C 59+ Dark yellowish brown (lOYR 4/6 m); loam; moderate, coarse, subangular blocky; firm; few, coarse, oblique, exped roots. -144- Classification, Diagnostic Horizons and/or Properties, Canadian System: Podzolic Bf horizon. Organic C = 0.5-5% FCp+Alp = 0.6% or more. Base saturation < 50% Orthic Humo-Ferric Podzol. U.S. Soil Taxonomy: Epipedon: Ochric Subsurface horizons: Cambic. Subsurface materials: None. Typic Cryochrept. -145- APPENDIX c Selected Physical and Chemical Properties o f Pedons 2, 3, 4, 6, 7, 8 ,10, 11 (upper slope), 11 (middle slope), 12, 13 -146- Pedon 2 - Selected physical and chemical properties HORIZON Ae Bfl BQ BC C Sand Clay Silt Texture Class % 66.2 59.8 58.5 66.0 67.4 % 3.20 3.20 3.40 2.40 4.60 % 30.6 36.9 38.1 31.6 28.0 C % sandy loam sandy loam sandy loam sandy loam sandy loam 0.81 2.1 2.1 1.7 0.68 N % 0.047 0.090 0.091 0.082 0.042 C/N pH dH ,0 pH 0.01 M CaCI, 17 23 23 21 16 4.5 5.0 5.4 5.5 6.1 3.6 4.1 4.3 4.6 5.1 Base Sat Extractable Cations by NH^OAc p H 7.0 (cmoK+ IkB') HORIZON AI Ca Fe K Mk Mn Na CEC C 0.022* 0.19 0.22 0.28 0.045 1.3 0.99 1.1 1.9 1.8 0,011* 0.011* 0.011* 0.011* 0.011* 0.0050* 0.028 0.088 0.0050* 0.0050* 0.22 0.25 0.20 0.28 0.27 0.0070* 0.0070* 0.0070* 0.0070* 0.0070* 0.020 0.020 0.033 0.024 0.044 3.9 4.9 3.4 3.7 2.7 % 39 26 42 61 79 HORIZON Al, Fe, At. Fe. ODOE* Fep+Alp orgC/Fe, .SFe.+AI, % 0.010 0.19 0.20 0.15 0.025 •/. 0.0060 0.50 0.31 0.14 0.047 % 0.055 0.31 0.40 0.34 0.18 % 0.025 0.34 0.22 0.12 0.047 (Pe,+AI,) /clay 1.1 1.4 0.016 0.69 0.50 0.29 0,072 0.0050 0.21 0.15 0.12 0.016 133 4.15 0.067 0.48 0.51 0.40 0.18 Ae Bfl BQ BC Ae Bfl BO BC C , = (NH4);C204 p= Na^P^O^ * = optical density o oxalate extract 1.7 1.4 0.32 #_ 6.84 12.1 14.6 = result lower than this detection limit Pedon 3 - Selected physical and chemical properties Texture Class C N % 26.0 sandy loam % 2.6 % 0.13 6.60 24.4 sandy loam 3.5 95.8 1.00 3.18 sand 97.5 0.700 1.76 sand HORIZON Sand Clay Silt Ae % 67.6 % 6.40 BQ! 69.1 eri2 BC C 94.8 0.800 4.41 sand pH pH dH ,0 0.01M CaCI, 20 4.4 3.6 0.18 19 4 2.7 0.11 25 4.7 5.1 4.3 3.1 0.095 32 5.2 4.5 0.082 20 5.3 4.5 CEC 8.0 % 18 4.9 1.9 II 12 1.3 2.0 23 7.1 1.7 C/N Base Sat Extractable Cations by NHjOAc p H 7.0 (cmoK+ Iks') HORIZON Mn 0.063 0.015 Na 0.029 0.019 0.025 Ms 0.42 0.18 0.044 0.0070* 0.11 0.011* 0.011* 0.15 0.0050* 0.021 0.018 0.0070* 0.0070* 0.017 0.036 0.013 Ai, % 0.065 Fe,+AI, (Fe,+AI,) /clay orgC/Fe, SFe.+Al. 0.034 0.082 17 10 0.24 0.62 BH2 BC 0.33 0.093 1.8 2.2 0.22 0.21 0.11 Fe. % 0.26 0.35 ODOE* % 0.15 Al. % 0.11 0.51 0.16 0.098 0.063 C 0.13 0.088 0.55 0.46 0.13 0.13 1.7 1.6 1.0 0.20 0.16 0.22 Ae BQl Bfi2 BC C HORIZON Ae Bm o = (NHJ2C2O4 AI 0.31 0.55 0.43 0.24 0.34 _ = Na4P207 Ca 0.82 0.33 0.14 Fe 0.041 0.049 0.028 K 0.14 0.0050* 0.10 * = 0.44 optical density o oxalate extract 0.54 0.20 0.23 0.27 28 0.58 49 19 0.62 #= _ result lower than this detection limit 0.53 Pedon 4 - Selected physical and chcmicai properties HORIZON Ahe Sand Clay Silt % % 15.2 % 54.1 Bml 30.7 29.9 15.4 Bm2 38.1 BC C Ae pH % 0.10 14 dH ,0 4.2 4.5 5.1 4.1 C N silt loam % 1.4 pH 0.01MCaCI, 3.5 16,4 54.7 45.5 silt loam loam 1.3 1.0 0.25 0.096 5.2 10 48.5 16.2 35.3 loam 0.48 0.24 2.0 5.2 4.2 60.4 18.6 21.0 sandv loam 0.31 0.048 6.4 5.5 4.4 Al 0.022" Extractable Cations by NH.OAc p H 7.0 (cmoK+ Ikg') K Mn Fe Mg Ca 0.038 0.19 0.90 2.0 0.011" 0.0060 0.31 0.048 0.011" 0.45 0.027 HORIZON Bml Bm2 BC C/N Texture Class 0.17 0.56 Na 0.023 CEC 6.9 6.1 3.8 3.6 5.4 3.8 Base Sat % 45 13 9.5 0.17 0.75 2.7 0.011" 0.011 0.011" 0.10 0.0050" 0.0050" 0.077 0.20 0.39 0.026 0.021 0.026 0.014 0.030 0.030 Al, •/• 0.0090 Fe. % 0.056 ODOE* F«,+AI, .5Fe.+A|, 0.32 43 0.053 Bml Bm2 BC 0.075 0.10 0.27 0.12 0.11 0.29 0.12 0.64 0.33 0.041 0.35 (Fe^+Ay /clay 0.0030 oig C/Fe, % 0.032 Al. % 0.025 0.023 0.26 0.14 7.5 0.11 C 0.035 0.041 0.045 0.050 0.014 0.0080 4.7 8.2 0.030 0.071 0.0040 8.5 0.059 C HORIZON Ae (NH4)2C204 0.27 0.025 0.072 = Na4?207 0.064 0.036 0.22 0.091 0.036 * = optical density o oxalate extract 0.22 # _ result lower than this detection limit 27 58 0.28 Pedon 6 - Selected physical and chemical properties. HORIZON Sand Clay Silt Texture Class % 37.4 pH dH ,0 pH 0.01M CaCI, Ae % 4.80 N % C/N % 57.9 C % sandy loam 1.4 0.074 19 5.3 4.5 Btje 51.5 7.20 41.3 sandy loam 2.0 0,25 7.9 5.5 4.9 C2 56.4 4.60 39.0 sandv loam 0.62 0.044 14 6.2 5.1 Al 0.022* Extractable Cations by NHLOAc p If 7.0 (cmoK+ 1kg') Fe K Mn Ca Me 0.0090 0.011* 0.0050* 1.4 4.1 Na 0.016 CEC 5.9 •/. 93 BtJs 0.022* 0.022 8.9 1.0x10' Cg 0.022* HORIZON _ HORIZON Ae . Base Sat 6.7 2.8 0.011* 0.053 2.3 0.0070* 0.011* 0.12 0.87 0.0070* 0.010 3.9** 71** Fe, •/. 0.029 Al. •/. 0.036 Fe. % 0.061 ODOE* Fe,+AI, orgC/Fe, •SFe.+AI. 0.78 0.046 (Fe,+AV> /clay 0.010 48 Btg Al, % 0.017 0.058 0.25 0.11 0.042 8.1 0.024 0.052 0.037 1.6 0.29 0.30 Cg . 0.27 0.043 0.067 0.24 0.076 0.017 12 0.058 Ae o = (NH^)2C%0 ^ p= Na^P^O; * = optical density of oxalate extract " = result lower than this detection limit ♦♦ = CEC by summation a a « r tu a r ;r e i a r a T w a S jii j- w n u a ' Pedon 7 - Selected physical and chemical properties. C/N pH % 0.060 13 dH ,0 4.3 2.7 0.10 27 2.3 0.11 20 Texture Class C N % 28.1 sandy loam % 0.78 5.20 21.0 sandy loam 78.3 2.60 19.1 loamy sand Ae Bf Al 0.022* 0.12 Extractable Cations by NILOAc p H 7.0 (cmoK+ 1kg') K Mn Ca Fe Me 0.15 0.012 0.24 1.2 0.011* 0.12 0.028 0.094 0.43 0.064 Na 0.035 CEC 2.6 •/. 60 0.011 5.9 11 C 0.30 0.16 0.031 0.033 0.030 0.010 0.014 2.8 8.5 HORIZON Al, % 0.0010 Fe, % 0.0040 Al. % 0.0090 Fe. % 0.010 ODOE* Fe,+Al, orgC/Fe, 5Fe.+Al. 0.090 0.0050 (Fe,+Al,) /clay 0.0020 1.9x10' 0.014 0.18 0.41 0.40 0.53 2.9 0.59 0.11 0.66 0.15 0.14 0.49 0.26 1.6 0.29 0.11 6.7 16 Sand Clay Silt Ae % 69.1 % 2.80 Bf 73.8 C HORIZON HORIZON Ae Bf C q= (NH^)zC20^ = Na^P^Oy * = optical density o: oxalate extract 4.4 4.6 pH 0.01MCaCI, 3.5 3.7 4.1 Base Sat #= _ result lower than this detection limit 0.62 Pedon 8 -Selected physica and chemical properties. Texture Class C N % 40.9 sandy loam % 0.58 % 0.045 34.9 sandy loam 2.9 0.13 BC 63.3 61.6 1.80 2.00 52.0 8.00 sandy loam loam/ sandv loam 1.8 € 36.4 40.0 0.37 HORIZON Ae Bf Sand Clay Silt % % 2.40 56.7 HORIZON Ae Bf BC C HORIZON Ae Bf BC C , = (NH4)2C;0^ Al 0.022* 0.012 0.40 0.18 13 pH dH ,0 4.3 pH 0.01M CaCI, 3.5 23 4.6 4 0.076 23 4.9 4.2 0.040 9.3 5.2 4.3 Extractable Cations by NH^OAc p M7.0 (cnsoK+ Ikg‘) K Mg Mn Ca Fe 0.012 1.0 0.011* 0.065 0.16 0.020 1.8 0.065 0.11 0.067 0.0050* 0.061 0.60 0.011 0.0090 0.41 0.011* 0.026 0.094 0.0070* Alp % 0.0020 Fe, % 0.0080 Al. % 0.0090 Fe. % 0.016 ODOE* Fep+Alp 0.011 0.12 0.18 0.061 0.53 0.12 0.046 0.24 0.43 0.10 0.77 0.23 0.040 0.24 2.9 1.6 0.060 p= Na^P^Oy * = optical density o oxalate extract C/N 0.65 0.30 0.11 Base Sat Na 0.0090 CEC 2.3 5.2 3.0 1.4 55 39 23 38 (Fe,+Alp) /clay 0.0050 0.36 org C/FCp •5Fe.+A|. 69 5.6 0.017 0,63 0.15 0.013 15 8.1 0.55 0.12 0.047 0.018 0.013 #= _ result lower than this detection limit Pedon 10 - Selected physical and chcmicai properties Clay % 6.60 Slit % 64.5 10.0 60.0 7.40 50.9 HORIZON Sand % Ae AB 28.9 30.0 BO 41.7 37.9 6.00 Al 0.022* Ca 2.8 0.016 2.2 2.0 _ AB Bfl . Cg 0.097 0.33 HORIZON Ac AB Bfl . . Cg silt loam silt loam silt loam silt loam C % 0.88 N % 0.060 0.74 0.75 1.0 C/N 0.062 15 12 pH dH ,0 4.5 4.6 0.11 0.076 7.1 14 4.8 5.1 Me 0.64 0.68 Mn 0.0070* 0.0070* Na 0.014 0.028 CEC 5.3 5.8 % 0.007 0.014 0.097 0.089 „ = ( N H ,)A Û 4 p = N a ,? A Fe 0.011* 0.011* K 0.0050* 0.033 0.12 0.098 0.50 0.020 0.031 F ', % 0.025 0.051 0.35 0.097 Al. •/. 0.019 0.031 Fe. % 0.035 0.17 0.20 0.084 0.37 0.13 % 65 52 0.83 0.21 0.0070* 0.0090 0.047 0.021 7.1 2.4 42 32 ODOE* Fe,+AI, orgC/Fe, .5FC.+AI. 0.34 0.33 1.5 0.032 (Fe,+AI^ /clay 0.0050 35 0.036 0.0070 0.060 14 2.2 11 0.073 0.35 0.26 optical density o oxalate extract 0.54 0.065 0.44 0.19 pH 0.01MCaCI, 3.8 3.9 4 4.2 Base Sat Extractable Cations by NH^OAc p H7.0 (cmoKf lltf') HORIZON Ae 56.1 Texture Class 0.031 result lower than this detection limit Pedon 1 (upper slope) - Selected physical and chemical properties. HORIZON Sand Clay Silt % % Ae 41.1 7.90 % 51.0 Bt BC 30.5 13.4 39.5 39.6 8.70 8.60 € HORIZON 56.1 51.8 51.9 Texture Class C % N C/N silt loam 0.87 % 0.055 silt loam 1.8 0.11 silt loam silt loam 1.1 0.31 0.064 17 18 0.016 19 Extractable Cations by NHLOAc p H 7.0 (cmoK+ Ca Fe K Mb 16 pH dH ,0 4.3 pH O.OIMCaCI, 3.5 4.4 3.8 4.7 4.7 4.1 4.2 Na CEC Base Sat. % 0.031 0.020 6.9 0.045 Ac Al 0.022* 0.36 1.9 1.1 0.011* 0.15 0.0050* Bt 0.15 0.45 0.26 7.0 34 23 BC C 0.29 0.35 0.21 0.25 0.011* 0.011 0.0050 * 0.096 0.079 0.062 0.020 0.016 0.0080 0.010 2.9 1.6 15 27 HORIZON F', % 0.018 Al. % 0.029 F«,+AI, SFe.+AI. 0.10 48 0.043 0.11 0.40 0.19 0.027 0.51 (Fe,+AI,) /clay 0.0030 0.038 orgC/Fe, Bt BC 4.5 0.45 0.083 0.12 0.18 Fe. % 0.028 0.51 0.16 ODOE* Ae Al, % 0.0090 0.023 C 0.046 0.061 0.081 0.063 0.10 9.6 5.1 0.25 0.11 (NH4)2C204 = Na4P202 * = optical density o oxalate extract 1.7 0.53 Mn 0.060 0.20 0.11 0.012 #= _ result lower than this detection limit Pedon 11 (middle slope) - Selected physical and chemical properties. . Bc nc : IC Clay sut Texture Class C 50.1 % 4.80 % 45.1 sandy loam % 0.36 76.3 5.40 18.4 loamy sand/ sandy loam 70.3 5.20 24.5 83.4 2.10 27.4 91.8 10.4 0.700 Sand HORIZON .......... . '< i k r A nc c B02 pH 0.01MCaCK 0.030 12 3.6 0.98 0.049 20 4.4 4.8 4.2 sandy loam 1.2 0.056 21 5.1 4.3 14.5 loamy sand 1.1 0.055 20 5.2 4.5 62.2 7.50 silt loam sand 0.54 1.0 0.032 0.049 17 21 5.3 5.6 4.5 4.7 , - 0.28 0.39 0.24 0.17 0.32 0.18 0.011* 0.011* 0.011* 0.069 0.079 0.029 Fcp+Alp 0.018 0.36 0.17 0.10 0.55 0.029 0.10 Fe. % 0.038 0.23 OpOE* 0.010 Al * 0.020 0.13 0.21 0.20 0.25 0.30 0.16 0.56 0.51 AI 0.12 0.14 0.17 nc c pH dH,0 0.30 > HORIZON # # # # # C/N E ztnm k c r n t i m by NHjOAc D Cm w m m '' 0.012 0.089 1.42 0.96 0.025 0.063 0.0050* 0.46 0.014 HORIZON Ac BQl 5 B02 ^ N 0.14 0.18 0.076 0.079 0.089 0.29 0.14 0.17 0.15 p = Na4P207 * = optical density oi oxalate extract „ = (NH4)2C204 * = results lower than this detection limit )kir‘) 0.046 0.020 0.035 0.018 Mn 0.026 0.029 0.010 0.032 CEC 4.9 3.1 1.8 0.0070* 0.0070* 0.0070* 0.013 1.9 0.0090 1.1 2.7** 1.1 25 85 22 (FCp+Alp) /day 0.0060 0.086 oigC /Fe, 4 F t+ A l 20 0.039 0.29 0.33 oil 0.079 0.14 0.42 0.47 0.34 0.37 0.17 0.32 Na 0.068 0.011 Base Sat. % 34 36 0.065 0.17 0.016 0.46 ** = CEC by summation. 2.7 5.6 5.4 6.9 6.0 31 0.37 0.21 0.36 Pedon 12 - Selected physical and chemical properties HORIZON Ae Bfj C Sand % 62.2 Clay % 3.90 Silt % 33.9 Texture Class 83.9 1.40 89.1 1.40 14.7 9.50 Bfl C HORIZON Ae Bfj C , = (NH^)2C20^ N % 0.067 C/N loamy sand 2.3 0.12 13 20 sand 1.5 0.075 19 pH dH ,0 3.9 pH 0.01MCaCI, 3.3 4.8 4.1 5.2 4.4 Raw Sat Extractable Cations by NH^OAc p M7.0 (cnoK-f Ikg') HORIZON Ae sandy loam C % 0.88 AI 0.27 0.25 1.1 0.85 0.33 0.55 Alp % 0.026 Fep O il 0.17 p= Na^PzO^ Cm Fe 0.026 0.050 0.015 0.036 Al. % 0.050 0.23 0.16 0.28 0.39 % K 0.0070 0.028 0.041 Fe. % 0.069 0.48 0.23 * = optical density o: oxalate extract Ms 0.22 Mn 0.028 0.13 0.072 0.017 0.011 ODOE* FCp+Alp 0.26 0.063 0.34 0.33 1.9 1.4 Na 0.020 0.0090* 0.0090* (Fep+Alp) /clay 0.016 0.24 0.23 CEC 5.8 % 2.9 1.8 23 34 36 org C/Fe, .5Fe,+AI, 24 10 0.085 0.52 9.4 0.51 # _= result lower than this detection limit Pedon 13 - Selected physical and chemical properties. HORIZON Sand Clay Silt Texture Class Ahe % 48.2 % 9.20 AB 47.3 10.4 % 42.6 42.3 loam loam er 51.7 9.60 38.7 loam/ sandy loam c 55.9 7.80 36.3 sandy loam Al Extractable Cations by NH^OAc p M7.0 (cnoK'f 1kg') K Fe Mn Ca Mg HORIZON Bf 0.33 0.022* 0.022* C 0.022* HORIZON Ahe Alp % 0.075 AB O il Bf O il 0.20 Ahe AB C , = (NH4)2C;0^ = Na^P^O^ C % N % C/N pH dH ,0 1.7 0.077 0.13 21 22 4.2 O il 0.14 2.7 2.2 2.4 pH O.OIMCaCI, 3.5 6.0 21 6.7 7.2 18 7.1 6.3 6.4 Base Sat. Na 0.040 0.019 CEC 12 18 0.031 0.035 15 12 1.2x10^ 1.1x10* 1.1x10* org C/Fe, SFe.+A|, 4.8 0.33 % 40 3.9 18 0.10 0.011* 0.21 0.081 0.67 2.9 17 12 0.011* 0.090 2.0 0.042 0.025 0.018 0.011* 0.052 1.5 0.014 Al. % O il Fe. % ODOE* F',+AI, 2.6 0.42 0.14 0.44 0.29 (F e ,+ A y /clay 0.045 2.1 0.57 0.054 5.9 0.28 O il 0.26 0.24 0.19 1.1 1.0 0.69 0.72 0,072 0.092 3.8 4.6 0.23 % 0.34 046 0.58 0.52 * = optical density of oxalate extract = result lower than this detection limit 0.35 APPENDIX D Complete Data Set from Nitrogen Analyses. 158- Sample # S ite# Horbom 64 65 116 117 68 69 120 121 12 73 124 125 76 77 128 129 80 81 132 133 84 85 136 137 88 89 140 141 92 93 144 145 96 97 148 149 100 101 152 153 104 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 6 6 6 6 7 7 7 7 8 8 8 8 9 9 9 9 10 10 10 10 11 Ahe Ahe Ahe Ahe Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae Ae C % 2.441 2 2.733 1.877 2.4 1.745 2.553 1.633 3.269 3.509 2.956 3.306 3.512 2.248 3.637 2.222 2.026 2.299 1.431 3.315 1.501 1.51 1.998 1.169 1.145 1.017 1.013 1.202 3.371 2.605 2.321 2.722 1.103 1.029 2.164 0.871 2.278 1.933 2.597 2.455 1.519 N % 0.135 0.093 0.101 0.047 0.129 0.081 0.089 0.134 0.187 0.19 0.134 0.29 0.197 0.123 0.314 0.098 0.012 0.132 0.062 0.16 0.071 0.064 0.084 0.042 0.068 0.062 0.048 0.068 0.146 0.108 0.106 0.042 0.048 0.048 0.109 0.215 0.076 0.108 0.04 0.042 0.091 -159- C/N 18.081 21.505 27.059 39.936 18.605 21.543 28.685 12.187 17.481 18.468 22.060 11.400 17.827 18.276 11.583 22.673 168.833 17.417 23.081 20.719 21.141 23.594 23.786 27.833 16.838 16.403 21.104 17.676 23.089 24.120 21.896 64.810 22.979 21.437 19.853 4.051 29.974 17.898 64.925 58.452 16.692 NO. ppm 0.40 0.15 0.45 0.15 5.15 3.15 4.25 2.60 0.10 0.10 0.00 0.00 1.45 0.10 0.80 0.20 0.45 0.15 0.10 0.00 11.60 12.40 5-75 10.60 0.75 0.60 0J25 0-10 7.40 9.05 5.35 6J20 0.30 0.25 0.15 0.00 0.35 12.15 0.10 6.60 1.75 NH. ppm 8.00 7-25 6.65 6.60 1225 12.45 8.55 7-95 13-35 8.80 10-90 9-65 24-30 22-05 15.85 22.15 13.25 25.30 8.40 14.90 6.30 9.05 1.95 4.95 13.55 19.25 6.05 8.80 11.70 19.60 9.00 16.20 6.20 8.35 3.15 3.35 19.50 13.30 1020 6.55 11.30 mim-N ppm 42 36.4 30.8 25.2 252 16.8 252 22-4 28 252 30.8 22.4 42 36.4 30.8 47.6 33.6 53.2 30.8 30.8 36.4 30.8 19.6 16.8 28 145.6 30.8 28 28 42 30.8 392 16.8 16.8 16.8 28 33.6 33.6 42 392 28 105 156 157 108 109 160 161 112 113 164 165 66 67 118 119 70 71 122 123 74 75 126 127 78 79 130 131 82 83 134 135 86 87 138 139 90 91 142 143 94 95 146 147 11 11 11 12 12 12 12 13 13 13 13 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 6 6 6 6 7 7 7 7 8 8 8 8 Ae Ae Ae Ae Ae Ae Ae Ahe Ahe Ahe Ahe Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bt Bt Bt Bt Bt Bt Bt Bt Bt Bt Bt Bt Bf Bf Bf Bf Bf Bf Bf Bf 1 0.081 1.418 1.057 0.055 1.057 0.055 2.516 Æ )(.01) 1.92 0242 0.115 2.339 0.139 2.593 4.467 0258 0.209 3.687 0.178 5.426 0.131 2.486 0.14 2.549 0.306 2.762 0.094 2.774 2.785 0.103 0.111 2.676 0.303 3.288 0.242 2.752 0.323 3.728 0.317 2.679 0.275 4.487 0.132 2.687 0.225 4.296 0.138 2.266 0.112 1.762 0.119 2.27 2.064 0.116 0.097 3.689 0.356 3.42 0.189 3.793 0.146 2.736 0.128 2.364 0.127 2.496 0.103 2226 0.116 2.418 0.457 4.338 0.229 3.933 0.333 3.213 0.593 4.77 02 3.611 0.261 4.701 0.042 2.722 0.181 3.599 -160- 17.506 19.218 19.218 ERR 7.934 20.339 18.655 17.314 17.641 30.483 18.977 18.207 9.026 29.511 27.039 24.108 10.851 11.372 11.542 8.451 16.316 20.356 19.093 16.420 15.732 19.076 17.793 38.031 9.607 20.069 18.740 18.469 19.654 21.612 20.845 9.492 17.175 9.649 8.044 18.055 18.011 64.810 19.884 0.15 0.60 0.00 0.25 0.15 0.00 0.00 13.55 9.80 10.85 820 4.70 3.20 5.60 3.80 6.20 1.70 7.85 1.40 0.15 0.20 0.05 0.00 0.95 2.35 0.85 1.90 0.10 22.00 0.00 15.90 12.20 14.05 9.55 11.45 2.10 3.50 0.85 1.20 27.55 23.75 19.50 23.85 10.35 5.35 4.55 9.80 11.80 3.90 6.15 7.85 5.90 5.85 425 6.15 6.80 5.95 5.80 13.10 15.30 7.65 13.95 8.90 7.80 7.10 5.60 7.95 10.05 5.15 6.25 13.50 5.45 7.10 2.15 6.45 4.10 3.85 1.85 9.20 7.65 1.65 2.95 8.70 9.10 5.05 10.20 22.4 392 19.6 28 22.4 252 36.4 39.2 16.8 39.2 22.4 47.6 61.6 14 58.8 44.8 53.2 392 36.4 22.4 25.2 22.4 19.6 22.4 224 25.2 16.8 56 36.4 36.4 252 64.4 33.6 392 33.6 252 252 28 33.6 72.8 78.4 84 78.4 98 99 150 151 102 103 154 155 106 107 158 159 110 111 162 163 114 115 166 167 168 170 173 176 179 182 185 188 191 193 195 197 203 205 207 209 212 214 218 220 222 225 228 9 9 9 9 10 10 10 10 11 11 11 11 12 12 12 12 13 13 13 13 1 1 1 2 2 2 3 3 3 4 4 4 6 6 7 7 7 8 9 9 9 10 10 Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf Bf L L L L L L L L L L L L L L L L L L L I. 1. 1, 3.3 3266 2.507 3298 1.788 2.654 2.152 2.548 1.405 2.803 1.604 2.283 2.372 3.245 2.626 3.299 2.345 2.919 224 3.675 40.12 43.84 37.25 46.08 41.25 34.9 42.93 43.56 41.21 39.5 40.27 38.62 4528 39.55 31.57 35.09 44.911 43.99 19.5 31.15 38.28 40.04 37.81 0.161 0.161 0.114 0.15 0.067 0.145 0.104 0.139 0.099 0.155 0.082 0.102 0.133 0.184 0.127 0.158 0.094 0.138 0.086 0.203 1.48 2.27 1.12 1.72 1.46 1.24 2.27 2.02 1.67 1.4 1.65 1.81 1.88 2.17 1.4 12 1.85 1.63 0.802 1.17 0.735 0.534 1,56 -loi 20.497 20286 21.991 21.987 26.687 18.303 20.692 18.331 14.192 18.084 19.561 22.382 17.835 17.636 20.677 20.880 24.947 21.152 26.047 18.103 27.108 19.313 33.259 26.791 28.253 28.145 18.912 21.564 24.677 28.214 24.406 21.337 24.085 18.226 22.550 29.242 24.276 26.988 24.314 26.624 52.082 74.981 24.237 14.50 16.05 9.75 8.60 10.60 11.75 9.50 9.65 1.10 3.20 0.30 1.75 0.10 0.20 0.00 0.05 7.40 8.55 6.40 7.10 0.95 6.40 9.75 1.15 0.40 2.70 1.55 0.35 0.20 0.45 0.40 0.35 49.45 83.98 2.50 0.00 2.20 3.70 36.50 5.00 1.40 164.87 39,30. 8.15 11.00 4.55 4.65 8.50 9.75 5.70 7.00 6.10 7.70 1.80 2.50 6.75 11.45 2.00 6.75 3.15 4.10 1.40 2.15 85.00 314.17 128.00 346.60 34.05 259.30 538.30 23.25 24.40 131.83 126.90 35.75 255.10 81.00 494.17 124.87 268.00 248.50 332.25 390.90 121.10 178.00 464.10 58.8 44.8 56 50.4 22.4 30.8 30.8 33.6 25.2 25.2 25.2 36.4 11.2 50.4 16.8 50.4 44.8 53.2 33.6 53.2 966 868 770 1036 812 658 2044 1036 1358 588 1190 1638 784 910 1358 868 1428 1624 462 1078 462 574 728 231 234 237 240 245 248 171 174 177 180 183 184 186 189 201 206 208 210 215 223 226 229 232 235 236 238 241 243 246 250 169 172 175 178 181 187 190 192 194 196 198 199 200 10 11 12 12 13 13 1 1 2 2 2 2 3 3 5 6 7 7 8 9 10 10 10 11 11 12 12 12 13 13 1 1 1 2 2 3 3 3 4 4 4 5 5 L L L L L L F F F F F H F F L+F F F F F F F F F F F F F F F F F+H H H H H H H F+H F+H F+H F+H L+F+H L+F+H 46.58 38.87 47.23 36.98 43.57 42.7 44.37 39.05 46.22 44.49 45.45 30.3 41.54 40.27 41.36 32.68 31.75 40.78 44.54 44.3 45.78 44.52 40.67 26.57 39.31 43.82 35.66 41.44 41.76 40.71 42.43 42.15 28.99 46.38 39.84 42.69 33.38 30.02 43.38 40.77 28.89 35.01 29.8 1.46 1.45 1.35 1.38 2.15 2.21 2.62 1.61 1.67 1.76 1.6 1.1 2.19 2.01 1.94 1.63 1.71 1.61 1.71 0.446 2.02 1.86 1.76 1.13 1.73 1.69 1.7 1.91 2.31 2.05 1.66 2.23 1.46 1.75 1.56 2.34 1.45 1.36 1.53 1.82 1.5 1.37 1.09 -162- 31.904 26.807 34.985 26.797 20.265 19.321 16.935 24.255 27.677 25.278 28.406 27.545 18.968 20.035 21.320 20.049 18.567 25.329 26.047 99.327 22.663 23.935 23.108 23.513 22.723 25.929 20.976 21.696 18.078 19.859 25.560 18.901 19.856 26.503 25.538 18.244 23.021 22.074 28.353 22.401 19.260 25.555 27.339 76.65 0.46 0.20 0.90 180.46 122.56 2.90 26.95 0.70 0.30 1.25 0.40 0.80 0.65 40.706 74.08 1.60 0.00 1.50 2.60 163.95 18.50 87.47 0.30 1.90 0.00 0.10 1.20 110.24 119.23 0.45 3.95 15.65 0.75 0.40 0.30 0.30 0.55 0.30 0.60 0.70 13.90 2.40 275.90 123.68 108.30 220.70 39.30 102.79 89.70 111.60 478.70 95.70 230.60 248.80 333.20 121.00 132.50 96.00 544.80 389.10 537.80 42.60 200.50 55520 267.80 105.50 93.50 69.00 102.50 66.00 44.30 41.50 31.45 146.30 32.50 647.40 68.50 109.30 26.70 94.90 71.40 180.50 35.75 25.40 30.30 770 714 434 462 476 560 1442 1134 1078 1232 560 476 1708 1596 378 966 1554 1022 1218 378 616 784 896 1064 1540 616 812 826 644 686 1176 1134 630 1190 630 1204 854 672 504 938 1638 616 308 202 204 211 213 216 217 219 221 224 227 230 233 239 242 244 247 249 251 6 6 7 1 8 8 9 9 9 10 10 10 12 12 12 13 13 13 F+H F+H H F+H H H F+H H H H H H H H H H H H 38.63 43.87 36.75 42.33 42.96 45.68 30.2 37.03 38.9 43.49 37.4 36.3 44.07 34.1 37.56 33.31 39.55 27.83 1.92 1.76 1.53 1.79 1.73 2.41 1.28 1.58 0.726 2.1 1.56 2.09 1.52 1.51 1.47 1.61 2.05 1.65 -163- 20.120 24.926 24.020 23.648 24.832 18.954 23.594 23.437 53.581 20.710 23.974 17.368 28.993 22.583 25.551 20.689 19.293 16.867 209.26 40.50 0.00 1.90 0.00 67.00 11.10 1.50 0.50 110.80 13.00 56.71 0.00 0.30 0.50 68.97 10524 50.64 266.00 84.00 205.90 514.20 226.30 135.50 99.80 318.30 53.20 164.40 321.40 222.90 82.90 51.30 51.50 2320 29.40 27.10 770 644 1302 1386 1862 1778 336 1148 406 616 1036 1246 952 882 840 434 518 322 NOTE TO USERS Oversize maps and charts are microfilmed in sections in the following manner: LEFT TO RIGHT, TOP TO BOTTOM, WITH SMALL OVERLAPS This reproduction is the best copy available. UMI Appendix A Associations (Dimow), Topography,and Material in the M cŒ egor Model Forest «HCREEKisomtofcHuriB-fWTiBPotafcnA:mod.art MMri, tiWi WERIL(OrthicHumo-FuriePodataiiKytant iibK.MlKnÉaK,MlI UNMZA(OilMeHiniD-fnifeM at andyIMIKmod. I ’NCTON [OrtMcHumo-FantcPndattBiicvrtdntaid) SEERdCH (OilMe H u m -F a k Podafc ia m r and: H i dotaidl aOMMCH MMb Hums-Rmtc FMafc tannc mad. nnl doOidl rOHY [OilMe H im -Fiente M at ondT taaic nod. M l dnindl BEZMKD [OftNc H im F en ie PBdafc an d y teuiE M l dninid, n a kERRICX lOrtNc Him-Fenie Padzot ondy ioni: ■■■dntnd] lUMSEY [OilMe Him-F«nle n d o fc tauqr and: npMÿ dndod] E/WPAWnaGE [MfdcHuiB-FiHTtenMatandyiBMCMadntadl CO dElom fcH iaa-W icPiidB ta iay leaii: »dl dnlindl CAPrM NCRaK tOi1NeHifnD-F«TteM Btandykni:iiiid.M ldnM I HWSER [OftMe a n y Liatafc E t ham: mod. m l dntnndl nwEWEW [GhyE G ay l« " B t hoey * y : dny. dm iall DESERTERS (Srunialc Qny l-uehDt ham: mad. h di dntnd] BOWRON (Bnnhoie Qiay L u rtat « • h tn c mad. M l dnthdl KDHESn [biadaole a n y Luetaot E l hnin: mod. M l dnlnadi GtSCOME (Ofttde OjErie Bnaihot ham yaaE: lafUlydnlnadl FONTONKO (Ekarlahd Dyalile Bnadaol: o n ly ham: M l dflMd. il|i« y DOME CREEK [EkivhlE Dyalifc BnaMd: nte npHlydrahad. anidialHall CHIEF [Typh Maaial: flbite: w iy yaody diaMd] MOXLEY[Itaie Fttrtaat tfefte: «Biy yaarfy diEadl SPNCWIHIKO [OflMc Hufidc Ghyaat aandy hanc ynaily dndnadi MCSREaOR [Bhyad Hainaal: ham: an*, dnhad] STELIAKO (ahyad Rapoaet aandy ham: paariy diatnd, any. diMhdl ROCKLAND [REiaE: bEiadc oaerhE Rom] WATBIIOOY 120000FORESTINVENTORYMAPSHEETlaUHOmiES 11:130 000 i m i NMM3 Zone 10 PlaiMhn Augu«14.1H7-HM FAas IMMnin Il II II II II II II II II II i m { I P i'jl Il II II II II II II II : ’ nI , m Il II II II II II II II 1 % 1 I I !■ I y Il II II II II II II II II f ek.kC._a» I Il II II II II II II II I tÊX» •* . QC H 1 I Ce ■of« rlM a M n A l " -- " _ _ _ _ _ _ _ _ r_ _ _ _ _ _ _ _ _ _ m Origrai maiipina «M cendiKtad at 1:100,1X10 -- -»--_____mI"#" TT A— - ^_ _. munrn'-