SOIL AND TOPOGRAPHIC FEATURES AFFECT PLANT GROWTH
ON A NATURAL GAS PIPELINE RIGHT-OF-WAY
IN NORTHEASTERN BRITISH COLUMBIA

by

Toby Turner
B.H.Sc., Flinders University of South Australia, 2000
B.Pl., University ofNorthem British Columbia, 20 11

THESIS SUBMITTED IN PARTIAL FULFILLMENT OF
THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE
IN
FORESTRY

UNIVERSITY OF NORTHERN BRITISH COLUMBIA
June 2016

© Toby Turner, 2016

Abstract
Natural gas reserves in northeastern British Columbia (B.C.) are being extracted, yet the
effects to soils and plants from industrial disturbance in the region are poorly understood.
This study examined soil and topographic factors that affect plant establishment and
growth on a reclaimed natural gas pipeline. The study area was located approximately 70
km southeast of Tumbler Ridge, B.C. Field sampling took place between spring 2012 and
summer 2013. Soil properties were examined to understand growing conditions at the site,
natural regeneration was observed to understand current species diversity, and growth
parameters were taken for lodgepole pine and shrubby cinquefoil. Soil nutrients were
higher in wetland blocks than upland blocks, and were associated with greater species
diversity. Plant growth was greatest in north-facing blocks, however biomass was greatest
in crest blocks. Reliance on natural revegetation can delay site recovery, and reclaiming a
site requires site-specific plant species in northeastern B.C.

11

Table of Contents
Abstract. .............................................................................................................................. . ii
Table of Contents ............................................................................................................... iii
List ofTables ...................................................................................................................... vi
List of Figures ................................................................................................................... viii
List of Acron)'Itls ................................................................................................................. x
Acknowledgements ............................................................................................................ xi
1.0 General Introduction ................................................................................................ 12
1.1 Research Objectives ................................................................................................. 12
1.2 Organization ofThesis ............................................................................................. 15
2. 0 Literature Review ........................................................................................................ 16
2.1 Boreal Forests .......................................................................................................... 16
2.1.2 BWBS and ESSF Biogeoclimatic Zones .......................................................... 19
2.2 Natural Gas in Northeastern B.C ............................................................................. 19
2.3 Disturbances Due to Pipelines ................................................................................. 20
2.3.1 Pipelines ............................................................................................................ 20
2.3.2 Forest Fragmentation .............................. .......................................................... 21
2.3.3 Soil Horizon Disturbance .................................................................................. 22
2.3.4 Other Disturbance Repercussions ..................................................................... 22
2.4 Reclamation of Pipeline Rights-of-Way .................................................................. 23
2.4.1 Regulatory Context ........................................................................................... 23
2.4.2 Goals ofReclamation ........................................................................................ 24
2.4.3 Plants ................................................................................................................. 24
2.4.4 Amendments ..................................................................................................... 25
2.4.5 Soil Properties ................................................................................................... 26
2.4.6 Topography ....................................................................................................... 29
3.0 Ojay Study Site ............................................................................................................ 32
4.0 Soil Properties and Topographic Features on a Reclaimed Pipeline RightOf-Way in Northeastern British Columbia .............................................................. 38
Abstract ...................................................................................................................... 3 8
4.1 Introduction .............................................................................................................. 39
4.2 Materials and Methods............................................................................................. 40
4.2.1 Study Site and Experimental Design ................................................................ 40
4.2.2 Sampling and Data Collection .......................................................................... 41
4.2.2.1 Soil Pits ....................................................................................................... 42
4.2.2.2 Soil Moisture .............................................................................................. 42
4.2.2.3 Soil Temperature ........................................................................................ 43
4.2.2.4 Bulk Density ............................................................................................... 43
4.2.2.5 Soil pH ........................................................................................................ 44

111

4.2.2.6 Additional Soil Properties, Cation Exchange Capacity, and
Texture ................................................................................................................... 44
4.2.2.7 Topography ................................................... .............................................. 44
4.2.3 Data Analysis .................................................................................................... 45
4.3 . Results ..................................................................................................................... 45
4.3. 1 Soil Pit Descriptions .......................................................................................... 45
4.3.2 Soil Moisture ..................................................................................................... 48
4.3.3 Soil Bulk Density .............................................................................................. 50
4.3.4 Soil Temperature ............................................................................................... 52
4.3.5 Soil Texture ....................................................................................................... 53
4.3.6 Soil pH .............................................................................................................. 54
4.3.7 Cation Exchange Capacity ................................................................................ 55
4.3.8 Macronutrients .................................................................................................. 59
4.3.9 Topography ....................................................................................................... 61
4.4 D iscussion ................................................................................................................ 62
4.4.1 BWBS biogeoclimatic zone .............................................................................. 62
4.4.2 ESSF biogeoclimatic zone ................................................................................ 64
4.5 Conclusion ............................................................................................................... 66
5.0 Plant Species Diversity on a Reclaimed Natural Gas Pipeline Right-ofWay in No11heastem British Colum bia .................................................................... 68
Abstract ...................................................................................................................... 68
5. 1 Introduction .............................................................................................................. 69
5.2 Materials and Methods............................................................................................. 70
5.2.1 Study Site and Experimental Design ................................................................ 70
5.2.2 Sampling and Data Collection .......................................................................... 71
5.2.3 Data Analysis ......................................................... ........................................... 73
5.4 Results ...................................................................................................................... 75
5.4.1 Species Diversity ............................................................................................... 77
5.5 Discussion ................................................................................................................ 81
5.5. 1 Aspect ................................................................................................................ 81
5.5.1.1 South-facing Blocks ................................................................................... 81
5.5.1.2 Crest Position Blocks ................................................................................. 82
5.5.1.3 North-facing Blocks ................................................................................... 84
5.5. 1.4 Wetlands ..................................................................................................... 85
5.5.2 Treatment .......................................................................................................... 87
5.5.2. 1 Control Plots ............................................................................................... 87
5.5.2.2 Pine Plots .................................................................................................... 88
5.5.2.3 Cinquefoil Plots .......................................................................................... 89
5.4.3 Limitations ........................................................................................................ 91
5.5 Conclusion ............................................................................................................... 92

IV

6.0 Growth and Survival of Lodgepole Pine and Shrubby Cinquefoil on a
Reclaimed Natural Gas Pipeline Right-of-Way in Northeastern British
Columbia .................................................................................................................. 93
Abstract ...................................................................................................................... 93
6.1 Introduction .............................................................................................................. 94
6.2 Materials and Methods ............................................................................................. 95
6.2.1 Study Site and Experimental Design ................................................................ 95
6.2.2 Sampling and Data Collection .......................................................................... 95
6.2.3 Data Analysis .................................................................................................... 97
6.3 Results ...................................................................................................................... 99
6.3 .1 Plant Growth ......................................................................................................... 99
6.3.1.1 Lodgepole Pine ........................................................................................... 99
6.3 .1.2 Shrubby Cinquefoil .................................................................................. 106
6.3 .1.3 Plant Mortality .......................................................................................... 114
6.4 Discussion .............................................................................................................. 115
6.4.1 Plant Height and Biomass ............................................................................... 115
6.4.1.1 Lodgepole Pine ......................................................................................... 115
6.4.1.2 Shrubby Cinquefoil .................................................................................. 117
6.4.2 Plant Survival .................................................................................................. 120
6.4.3 Limitations ...................................................................................................... 122
6.5 Conclusion ............................................................................................................. 122
7.0 Synthesis ofResults ................................................................................................... 124
Literature Cited ................................................................................................................ 126
Appendix 1. Soil Analysis ............................................................................................... 145
Appendix 2. Complete list of species planted in Ojay research blocks ........................... 146
Appendix 3. Alternative Species Diversity Index including Planted Lodgepole
Pine and Shrubby Cinquefoil ................................................................................. 148
Appendix 3A. Cover by Plant Type Including Planted Lodgepole Pine and
Shrubby Cinquefoil ............................................................................................ 148
Appendix 3B. Count by Plant Type Including Planted Lodgepole Pine and
Shrubby Cinquefoil ............................................................................................ 149
Appendix 3C. Diversity Index Values Including Planted Lodgepole Pine and
Shrubby Cinquefoil ............................................................................................ 150

v

List of Tables
Table 1. Location, elevation, forest type and dominant canopy species at Ojay
research blocks ......................................................................................................... 35
Table 2. Soi l moisture and nutrient regimes for each block. ............................................. 41
Table 3. Number of soil samples taken from each plot, block and
biogeoclimatic zone in 2012 .................................................................................... 42
Table 4. Soil pit organic layer features for right-of-way and forest upland
blocks ....................................................................................................................... 46
Table 5. Soil mineral layers for right-of-way and forest sample pits in upland
blocks ....................................................................................................................... 47
Table 6. Particle size (means and standard errors reported in parentheses) for
sand, silt and clay with associated soil class for upland blocks ............................... 54
Table 7. Mean CEC and exchangeable cations (AJ, Ca, Fe, K , Mg, Mn, N a) and
standard error(±) (Cmol (+) Kg' 1) of soil in upland blocks .................................... 57
Table 8. Mean and standard error (±) of exchangeable cations (AI, Ca, Fe, K ,
Mg, Mn, Na) and effective CEC (Cmol (+) Kg' 1) of soil in wetland
blocks ....................................................................................................................... 58
Table 9. Mean and standard error (expressed in parentheses) of major nutrients
(nitrogen, sulphur, phosphorous and potassium) and soil carbon in upland
blocks ....................................................................................................................... 59
Table 10. Mean and standard error (expressed in parentheses) of major
nutrients (nitrogen, sulphur, phosphorus and potassium) and soil carbon
in wetland blocks all treatments ............................................................................... 60
Table 11. Topographic variables of each block. ............................... ............ ..................... 61
Table 12. Mean and standard error (in parentheses) of naturally regenerated
species diversity, abundance, and Shannon Diversity Index (H') value of
upland blocks........................................................................................................... 77
Table 13. Mean and standard error (in parentheses) of naturally regenerated
species diversity, abundance and Shannon Diversity Index (H') values of
wetland blocks .......................................................................................................... 78
Table 14. Hierarchical regression for species diversity in combined control,
pine and cinquefoil plots, all blocks ......................................................................... 79
Table 15. Hierarchical regression for species diversity in separate control, pine
and cinquefoil plots, all blocks................................................................................ 80
Table 16. Biogeoclimatic zone, block designation, and numbers of pine and
cinquefoil seedlings selected for monitoring in 2012 and 2013 .............................. 96
Table 17. Mean plant height and stem diameter with standard error ((±)
reported in parentheses) of upland lodgepole pine for 20 12 and 2013 .................. I 02
Table 18. Mean plant height stem diameter and interannual change (standard
error reported in parentheses) oflodgepole pine in wetland blocks. ..................... 102

Vl

Table 19. Height diameter ratio (HDR) for lodgepole pine in 2012 and 2013
plus interannual change; standard error(±) reported in parentheses ..................... 103
Table 20. Results of mixed effects regression for lodgepole pine total height,
stem diameter, and HDR........................................................................................ 104
Table 21. Mean whole plant oven-dry biomass with standard error (reported in
parentheses) of lodgepole pine seedlings ............................................................... 105
Table 22. Mean whole plant biomass with standard error (reported in
parentheses) of lodgepole pine in wetland blocks ................................................. 105
Table 23. Mean plant height and cover area (standard error reported in
parentheses) for 2012 and 2013 with interannual change, shrubby
cinquefoil upland blocks........................................................................................ 110
Table 24. Mean plant height and cover area (standard error reported in
parentheses) with interannual change shrubby cinquefoil wetland blocks ............ 110
Table 25. Hierarchical regression of cinquefoil height and cover area........................... 111
Table 26. Mean and standard error (reported in parentheses) of whole plant
oven-dry biomass shrubby cinquefoil in upland blocks ......................................... 112
Table 27. Mean and standard error (reported in parentheses) of whole plant
biomass shrubby cinquefoil in wetland blocks .................... .................................. 112
Table 28. Hierarchical regression for cinquefoil biomass ............................................... 113

Vll

List of Figures
Figure 1. Example of pipeline construction spacing and layout of soil
(Desserud eta/. 2010) .............................................................................................. 21
Figure 2. Location map of Ojay study site in northeastem British Columbia................... 33
Figure 3. Coarse woody debris (CWD) applications in the BWBS 3 and ESSF
3 north facing blocks (M. Sherrington photos) ........................................................ 34
Figure 4. Sample block layout showing pipe trench (green rectangular box) and
plot locations within block boundaries .............................................................................. 36
Figure 5. BWBS 3 (north-facing block) right-of-way soil pit showing seep at
approximately 60 em depth...................................................................................... 48
Figure 6. Mean soil moisture with standard en-or in upland blocks for 2012 and
2013 .......................................................................................................................... 49
Figure 7. Mean soil moisture with standard error in wetland blocks for 2012
and 2013 growing seasons ....................................................................................... 49
Figure 8. Mean snowpack depth with standard en-or winter 2012-2013 ........................... 50
Figure 9. Mean and standard error of bulk density on pipeline right-of-way
(ROW) and forest in upland blocks ......................................................................... 51
Figure 10. Mean and standard error of bulk density on pipeline right-of-way
and forest in wetland blocks..................................................................................... 52
Figure 11. Mean soil temperature in all blocks in 2013 .................................................... 53
Figure 12. Mean and standard error of soil pH for Control, Pine, and Cinquefoil
plots .......................................................................................................................... 55
Figure 13. Mean and standard error ofCEC (cmol (+) Kg-1) with standard error
of upland blocks ....................................................................................................... 56
Figure 14. Mean and standard error ofCEC (cmol (+) Kg"1) in wetland blocks .............. 56
Figure 15. ESSF 3 (north-facing block) showing slope failure on left and right
sites of right-of-way ................................................................................................. 62
Figure 16. Data collection for species diversity, showing square for
inclusion/exclusion of plants .................................................................................... 72
Figure 17. Mean with standard error of species diversity (H') value by
treatment. .................................................................................................................. 75
Figure 18. Mean with standard error of species diversity (H') value by aspect
(block) ...................................................................................................................... 76
Figure 19. Mean and standard error (error bars) of natural regeneration
Shannon Diversity Index (H~ values for Control, Pine and Cinquefoil
plots, all blocks ........................................................................................................ 78
Figure 20. Images of south-facing blocks (top: BWBS 1, bottom: ESSF l)
showing natural regeneration recovery.................................................................... 82
Figure 2 1. Images of crest position blocks (top: BWBS 2, bottom: ESSF 2)
showing natural regeneration recovery.................................................................... 83

Vlll

Figure 22. Image of north-facing BWBS block showing natural regeneration
recovery .................................................................................................................... 84
Figure 23. Image of north-facing ESSF block showing natural regeneration
recovery.................................................................................................................... 85
Figure 24. Images of wetland blocks (top: BWBS 4, bottom: ESSF 4) showing
natural regeneration recovery................................................................................... 86
Figure 25. BWBS wetland block showing prevalence ofbluejoint (C.
canadensis) ............................................................................................................... 89
Figure 26. Cinquefoil plot at ESSF crest block, demonstrating low species
diversity observations............................................ .................................................. 90
Figure 27. Mean and standard error of pine seedling height by block............................ 100
Figure 28. Mean stem diameter with standard error by aspect (block) ........................... 100
Figure 29. Mean plant height with standard error (lodgepole pine) for 2012 and
2013 seasons ...................................................................... .................................... 101
Figure 30. Mean and standard error of Height-Diameter Ratio by block. ...................... 103
Figure 31. Mean above and below ground biomass with standard error of ovendry lodgepole pine seedlings in all blocks ............................................................. 105
Figure 32. Mean and standard error of cinquefoil height by aspect (block) ................... 107
Figure 33. Mean plant height and standard error for 2012 and 2013 shrubby
cinquefoil all blocks ............................................................................................... 107
Figure 34. Mean and standard error of cinquefoil cover area by block .......................... 108
Figure 3 5. Mean and standard error of belowground (root) biomass by block............... 111
Figure 36. Mean above and belowground plant biomass shrubby cinquefoil all
blocks ..................................................................................................................... 113
Figure 37. Lodgepole pine seedling mortality (mean and SE) in all blocks ................... 114

IX

List of Acronyms
ALC- Agricultural Land Commission
ALR- Agricultural Land Reserve
BWBS- Boreal White and Black Spruce
BC- British Columbia
BC MFLNRO- British Columbia Ministry of Forests, Lands, and Natural Resource
Operations
BCOGC- British Columbia Oil and Gas Commission
CEC- Cation Exchange Capacity
CWD- Coarse Woody Debris
ESSF- Engelmann Spruce Subalpine Fir
GPS- Global Positioning System
HDR- Height-Diameter Ratio
IOGC- Indian Oil and Gas Canada
LFH- surface litter (organic horizon on mineral soil)
MRD- Minimum Replacement Depth
NEB- National Energy Board
OM- Organic Matter
ROW- Right-Of-Way
SDI- Shannon Diversity Index
SOH- Stem Only Harvest
TCF- Trillion Cubic Feet
TOC- Total Organic Carbon
UNBC- University ofNorthem British Columbia

X

Acknowledgements
I would like to express my heartfelt gratitude to my supervisors, Dr. Chris Opio and Dr.
Mike Rutherford for their guidance and supervision; and my committee members Hugues
Massicotte and Stephane Dube for their vital feedback and assistance with soil and plant
identification; Shell Canada for funding this project, Mark Sherrington of Shell Canada
(Calgary); the University ofNorthem British Columbia Seed grant for additional funding;
Tim Gurlitz, Steve Rogers, Cory Hagen and Dustin Listhaeghe of Shell Canada (Grande
Prairie) for issuing work permits for monitoring. My thanks also go to Andrew CallJenter
ofReclaimit Ltd. for my understanding of the planting methodology used at the sites, and
ongoing guidance.

Other people at UNBC I would like to thank are Paul Sanborn, soil science professor, for
use of soil classification forms and guidance; and John Orlowsky and Doug Thompson for
granting me access to the Enhanced Forestry Laboratory (EFL) for plant and soil
preparation for analysis. I would also like to thank Dr. Che Elkin for help with statistics.
I would also like to thank my Research Assistant Ewing Teen for his invaluable field help,
and Dean Zimmer of the BC Oil and Gas Commission (Fort St. John) for lending me field
assistants (Cierra Hoecherl and Emilia Sasso) at very short notice in 2013. Further thanks
go to Stephane Dube, Bethany Wood, and Veronique Dube (BC Ministry of Forests Lands
and Natural Resource Operations- Omineca Region) for help and guidance with soil data
collection and analysis.
Lastly, 1 would like to thank Kari Harder (University of Alberta), for much needed help
with statistical analysis and for keeping me sane throughout this process.

XI

1.0 General Introduction
There are extensive natural gas reserves in northeastern British Columbia (B.C.). This resource
has attracted major oil and gas players to the region, and many companies have existing
infrastructure for extraction and transfer of natural gas. Reclamation requirements are in fo rce,
and general guidelines are available to industry; some companies are more proactive in their
efforts for improved reclamation practices that enhance vegetation recovery beyond
jurisdictional requirements. Beyond present guidelines, there are opportunities to optimize best
practices for soil handling and re-creation of plant communities, especially in mountainous and
subalpine environments.
1.1 Research Objectives
Exploration and extraction of western Canada's natural resources continues to be a national
economic driver, and natural gas reserves are found in abundance in this area of the country (BC
Ministry of Energy, Mines and Natural Gas, 201 2). Recent declines in commodity prices have
however, slowed exploration of natural gas. A significant proportion of extraction of natural gas
takes place in northeastern B.C. As more deposits of gas are explored and extracted, the
cumulative footprint of industrial disturbances grows (Foote and Krogman 2006; Olson and
Doherty 20 12), and so does the need to reclaim natural gas infrastructure.
Like many other companies, Shell Canada has goals and requirements for re-creating wildlife
habitat and restoring environmental quality following the installation ofpipelines. Part of this
comes from federal and provincial environmental legislation regarding reclamation of
industrially disturbed sites (Noble 2006), and from within the company' s stewardship role for
restoring environmental integrity to a site disturbed for resource extraction. Southern populations

12

of woodland caribou (Rangifer tarandus caribou) are threatened in part by human activities
including pipeline development (Edmonds 1998; Polfus eta/. 2011; Seip 1998), and recent
attention to these wildlife populations means that reclamation of sites along migration routes of
caribou should include re-establishment of critical, appropriately vegetated habitat (EC 2012;
Polfus et al. 2011 ).
The reclamation work undertaken by an oil and gas company, pipeline company or reclamation
contractor may also tie in with other long-term goals, such as addressing how resource
extraction, pipeline installation and reclamation activities impact First Nations' use of the land.
Traditional use of lands may include hunting and use of cet1ain plant species for medicinal
purposes or food. Meaningful consultation with First Nations is a part of the B.C. environmental
review process for obtaining approval for a specific project (Wyatt 2008), and understanding the
cultural practices ofNations affected by industrial development should be integral to assisting
with industry's reclamation goals (Baker and McLeJland 2003; Booth and Skelton 2011).
Depending on specific environmental factors, natural gas developments that affect surficial
horizons of forests and wetlands may take place during winter, when machinery operating on
frozen soils reduces potential for soil compaction and its associated effects on soil physical
characteristics such as air porosity and bulk density (Petter et al. 2009), and resources lost
through stuck machinery. A confounding factor for development is that climatic conditions of the
Peace region of northeastern B.C. include periodic freeze thaw cycles during the winter months
due to warming foehn or "Chinook" winds. These wind events increase ambient temperatures for
a period of time, melt snowpacks, and thaw topsoil layers (Bullock eta/. 2001; Walker eta/.
2006), which can create conditions for winter desiccation impacts to some plant species. This

13

highlights the importance of considering climate related factors when planning reclamation
strategies.
Although research and guidelines exist for reclamation best practices of various landscapes in
western Canada (Desserud eta/. 201 0; Desserud and Naeth 201 0; Naeth eta/. 1987), there are
knowledge gaps in understanding optimal reclamation and revegetation strategies at a micro site
level on pipeline rights-of-way (ROWs) in the Peace region of northeastern B.C. In this region, it
is not known which native plants species are best suited to specific site conditions, or if natural
regeneration is a sufficient strategy to re-establish vegetation at sites following creation of rightof-ways and installation of pipe trenches. Replanting programs can be expensive, and natural
regeneration may not be a suitable option for re-establishing vegetation at these sites. Further,
use of plant species native to the site and region, and mitigation of soil disturbances common to
industrial activity may lead to improved survival and growth of plant species used in reclamation
projects.
This research assessed soil properties, topographic features and plant growth and survival on a
reclaimed pipeline right-of-way in northeastern B.C. Within the pipeline right-of-way context,
the objectives of the study were to: (i) describe soil chemical and physical properties, and
topographic factors present; (ii) investigate plant species diversity, as forest plant species
heterogeneity may be an indicator of improved ecosystem health (Lindenmayer eta/. 2000;
Niemi and MacDonald 2004); and (iii) observe annual changes in plant growth, which is an
indicator of site recovery (Cieszewski and Bella 1989).

14

1.2 Organization of Thesis
This thesis is organized in a manuscript format. Chapter One provides the context for the study
with respect to vegetation communities found in the boreal region of northeastern B.C. Chapter
Two is a literature review of natural gas extraction sites in the Peace region of B.C., and the
challenges of reclaiming linear disturbances and substrate alterations caused by construction of
buried pipelines. Chapter Three presents information on the Ojay pipeline and the experimental
design of right-of-way research blocks used in this study. Chapter Four presents detailed
information on soil and topographic properties observed at the research sites. Chapter Five
examines plant species diversity using the Shannon Diversity Index in the research blocks along
the right-of-way. Chapter Six examines plant growth, determined by height, stem diameter and
plant biomass in research blocks along the right-of-way. Chapter Seven provides a summary of
the results of the study, the significance of the research findings to literature and industry,
limitations of the study, and recommendations for reclamation practice and directions for future
research.

15

2.0 Literature Review
The ecologically critical boreal forests of the northern hemisphere are found through much of
Canada, including the not1heastem region of B.C. Natural gas is found in the region of B.C., and
extraction of the resource in recent years has fragmented forests, altered soil properties, and
disrupted cultural use of the land base. Recent revisions to reclamation practice have improved
vegetation recovery, although substantial challenges remain in terms of mitigating industrial
impacts in montane ecosystems in northeastern B.C.

2.1 Boreal Forests
Canada has approximately 30% of the world ' s boreal forests and they encompass approximately
one third of Canada 's land mass (Brandt 2009: NRC 20 12; Smith et al. 2003). Recognized as
being of particular importance in a global context, the connectivity of boreal forests in Canada
are being altered through resource development (Lee and Boutin 2006). Boreal forests are
dynamic in that they undergo a variety of natural disturbances, su ch as fire and insect outbreaks
(McCullough eta/. 1998). Approximately fi ve to six million hectares of Canada ' s boreal forests
are disturbed by fire, insects and disease events per year, allegedly five to six times the area of
boreal forest that experiences disturbance from construction of pipeline right-of-ways over the
same time period (Bose eta/. 20 14; NRC 2012).
The south Peace region of northeastern B.C. incorporates a portion of Canada' s boreal fo rest.
The Boreal White and Black Spruce (BWBS) biogeoclimatic zone in northern B.C. includes the
eastern slopes of the Rocky Mountain range to the Alberta plains in the not1heastern comer of
B.C., and lower (below 1100 metres above sea level) elevations of northwestern B.C.,
incorporating approximately ten percent of the B .C. landmass (DeLong eta/. 1991; Prescott et
a!. 2000).
16

Industrial disturbances do not necessarily miiTor natural disturbance patterns (Bergeron eta/.
1999) experienced by forest ecosystems. Natural gas exploration activity in the northern regions
of B.C. has been extensive, and its footprint alters forest landscapes (Graf2009; Lee and Boutin
2006; Lovich and Bainbridge 1999; MacDonald et a!. 20 12). The harvest of strips of forest
stands for pipeline sites create linear corridors, and pipeline installations disturb soils through
construction of trenches for laying underground pipes. Tree harvest and removal, and substrate
disturbance for installation of pipelines, create numerous challenges for right-of-way
reclamation.
The benefits of reclaiming pipeline rights-of-way are not limited to restoring vegetation and soil
quality. Boreal forests in western Canada also provide critical habitat fo r charismatic animal
species such as grizzly bear (Ursus arctos horribilis) (Garshelis eta!. 2005), and southern
populations of woodland caribou (Rangifer tarandus caribou) (Wittmer eta!. 2007). Populations
of these species continue to decline in part due to direct and indirect ramifications of human
activities (Festa-Bianchet eta!. 201 1; Laberee et a!. 2014; McLoughlin eta/. 2003). Therefore,
reclamation strategies need to consider habitat requirements of wildlife when planning
reclamation of pipeline rights-of-way.
Boreal forests in western Canada are host to a variety of tree species including lodgepole pine

(Pinus contorta var. latifolia), white spruce (Picea glauca), black spruce (Picea mariana), jack
pine (Pinus banksiana), balsam poplar (Populus balsamifera), trembling aspen (Populus

tremuloides) and white (paper) birch (Betula papyrifera) (Thompson and Pitt 2003). Forest
practices also play a role in the composition of canopy species in forest stands (Barbier eta!.
2008). In B.C., lodgepole pine, with its range of tolerance of nutrient and moisture regimes, plus
its natural occurrence in interior regions, has been the principal tree species preferred for
17

mainland timber production (Brockley 1990; Coupe eta!. 1991 ). This species has been planted
extensively in interior regions of the province, and estimates suggest over fifty percent of interior
forests are planted with lodgepole pine (Mather eta!. 2010).
Understory vegetation is another integral component of a forest ecosystem (Chavez and
Macdonald 201 0) and species composition of forest understory is a key indicator of site quality
(Berger and Puettmann 2000; Strong eta!. 1991). Understory layers of a forest ecosystem help to
regulate carbon dynamics and capacity as sources of macro nutrients (nitrogen, phosphorus and
potassium) in a boreal forest soil community (Lagerstrom eta/. 2013; Mariani et al. 2006;
Nilsson and Wardle 2005). The herbaceous layer and its component species, coupled with
succession stages over time, demonstrates changes in forest plant community dynamics (Gilliam
2007; Nilsson and Wardle 2005).
There are complex interactions among and between plant species within an ecosystem (Pugnaire
and Luque 2001 ). A determinant of heterogeneity of understory species is the influence of the
dominant canopy species; their leaf litter physical and chemical values can influence the
diversity of understory plant communities (Berger and Puettmann 2000; MacDonald and Fenniak
2007; Lagerstrom eta!. 2013). In some instances, other plants act as competitors; and the
competitive nature of some plant species, along with other adaptations such as plasticity of
reproduction, allelopathy, or fast growth rates, benefits one species at the detriment to others. In
other circumstances, interaction of plants may facilitate plant growth among other individuals, of
the same or other species (Callaway and Walker 1997; Gomez-Aparicio et al. 2004; Treberg and
Turkington 201 0) or as nurse plants for seedlings (Barbour eta/. 1987; Schulze et al. 2005).

18

2.1.2 BWBS and ESSF Biogeoclimatic Zones
For ecological and forest management values, B.C. has been divided into 14 zones according to
geography, climate, and associated plant species. Two of these are found in the Peace region of
northeastern B.C., the Boreal White and Black Spruce (BWBS), and the Engelmann SpruceSubalpine Fir (ESSF) zones. These zones are further divided into subzones that indicate the
typical soil moisture range and climate, and the variant, which indicates plant associations (Pojar

et al. 1991).

Typical climatic conditions for the BWBS zone include mean annual temperature range between
-2.9• C to +2. C. Mean precipitation values for this zone vary between 330 mm and 570 mm, with
35% to 55% falling as snow (DeLong eta!. 1991). In northeastern B.C. on the eastern slopes of
the Rocky Mountains, the wet cool (wk) is a dominant subzone, and forests are dominated by
lodgepole pine and white spruce (DeLong eta/. 1991 ).

Features of the ESSF zone in northeastern B.C. include a mean annual temperature varying
between -2· C and +2. C. Temperatures below freezing (0. C) persist for five to seven months per
year. Annual precipitation values in this zone vary widely, with some regions receiving 400 mm
per year, whilst others receive up to 2200 rnm for the same period, with between 50% and 70%
falling as snow (Coupe eta/. 1991 ). The variability in snowfall within the ESSF zone means
subzones vary according to precipitation, and the moist very cold (mv) subzone is found in
northeastern B.C.
2.2 Natural Gas in Northeastern B.C.
The Peace region is part of the Western Canadian Sedimentary Basin, which spans from
northeastern B.C. at its western edge, eastward through much of Alberta, and further through

19

Saskatchewan and Manitoba (USGS 20 13). Some research asserts that petroleum deposits in this
basin are among the world's largest hydrocarbon sources, development for which began in the
1950s (Jones 1995; MacKendrick et al. 2001; Schneider eta!. 2003). The BC Ministry of
Energy, Mines and Natural Gas figures from 2006 assert that the Western Canada Sedimentary
Basin had 52 Tcf (Trillion cubic feet) of natural gas available, as well as 60 Tcf of CBG (Coal
Bed Gas). Estimated extraction figures for the south Peace region ofBC were around 15,000
Tcf/d (Trillion cubic feet per day) (BC Ministry of Energy, Mines and Natural Gas 2012).
2.3 Disturbances Due to Pipelines
2.3.1 Pipelines
Transportation of natural gas in Canada utilizes truck, rail, and pipeline options. Pipelines are an
efficient, if controversial, method of transporting petroleum products from the source to
distribution centres and markets (Brito and de Almeida 2009; Ericson 2009; NRC 2013). Natural
gas is a difficult product to transport, as its low density in gaseous form is expensive relative to
useable product to the end user (Ericson 2009). The need to compress natural gas for most
efficient transport requires specialized pipes as it requires storage and transportation under high
pressure, and ideally under low temperatures, to maintain a sufficient bulk density that provides
an acceptable cost and benefit to the purchaser (Thomas and Dawe 2003).

Construction of pipelines in forest ecosystems involves tree and other vegetation removal to
create a right-of-way between fifteen to thirty metres wide (Desserud eta/. 2010). This is
followed by trench digging, when soils are piled according to horizon (A, and B and C horizons,
Figure 1). One side of the trench is generally reserved for soil storage, and the other side of the
trench is used for vehicle and machinery access. These protocols can have adverse effects on soil

20

physical and chemical properties through soil compaction and mixing of soil horizons, and
nutrient loss through leaching when soils are piled for a period of time, and left open to
precipitation infiltration (Naeth et al. 1987; Shi eta!. 2014).

Topsoil stripped
from ROW

Pipeline
construction
equipment

Soil from

2m

--1

1-

Right-of-way (ROW)
(1 5 - 30m)
Figure I. Example of pipeline construction spacing and layout of soil (Desserud eta/. 201 0).

2.3.2 Forest Fragmentation
The installation of natural gas infrastructure in forest ecosystems alters continuity of forest cover
(Lee and Boutin 2006). The removal of trees for right-of-way construction may differ from
forestry practices that utilize partial cut harvesting, while all vegetation is removed during rightof-way construction (Thorpe and Thomas 2007; Man et at. 2008). Boreal fo rest ecosystems are
disturbance based, driven by fire, wind events, or insect outbreaks. Plant species that respond
favourably to disturbance thrive in boreal ecosystems (McCullough eta/. 1998). Natural
disturbances facilitate germination of species with serotinous cones, and increase volumes of
coarse woody debris, which is not always emulated by human-based disturbances (Schwilk and
Ackerly 200 I; Schoennagel et al. 2003).

21

2.3.3 Soil Horizon Disturbance
During construction of trenches for installing natural gas pipelines, forest soils undergo some
level of disturbance (Prose et al. 1987), which includes disturbance of soi l horizon layers.
Industrial activities may further affect soil structure and water relations through compaction due
to seasonal variations in soil sn·ength (Olson and Doherty 2012). In the instance of forest
harvesting, the impacts of repeated passes by tree harvest and removal equipment can cause soil
compaction in moist soils (Reeves eta!. 20 12; Sutherland 2003 ). Ground-based timber
harvesting for well pad and pipeline construction impacts on soil depends in part on topography
and soil texture (Reeves eta!. 2012). Forest harvest guidelines in B.C. recommend tree harvest
should be seasonal, identifying periods when soils may better withstand impacts of heavy
machinery used in timber harvest (MacDonald 1999; Petter eta/. 2009; Reeves eta!. 2012).
Seasonal variances in soil strength are in part due to moisture content, so spring is usually a time
when soils are typically wetter, and therefore have less strength, and are often inappropriate
times for forest harvest and other industrial activity. Late summer and winter may be preferable
for use of heavy machinery when soil compaction can be minimized due to low soil moisture
values, and frozen ground in winter (Sutherland 2003). Other complexities arise when
constructing sites on or near wetlands, as there may be unfrozen layers under the frost table
(Wright eta/. 2009).

2.3.4 Other Disturbance Repercussions
There are other environmental and social consequences related to pipeline development. On a
local scale, human activities can facilitate establishment of invasive plant species through canopy
openings, or when vehicles or equipment act as vectors (Cody eta/. 2000; Byers 2002; Olsen and
Doherty 2012). On a landscape scale, there can be consequences for wildlife and fish, noise

22

pollution and air quality concerns, particu larly during the construction phase of a pipeline (Van
Hinte et al. 2007). Pipeline right-of-ways impact forest ecosystems by fragmenting mature forest
stands (Nitschke 2008), disrupt caribou migration patterns (Dyer eta/. 200 1), and increase wolf
predation of caribou by line-of-sight creation (Latham et a/. 20 ll ). Social consequences of
pipeline development have been associated with decline in social fabric, shrinking productive
trapping areas, and lower participation in traditional activities for people in First Nations
communities (Angell and Parkins 201 1).
2.4 Reclamation of Pipeline Rights-of-Way

2.4.1 Regulatory Context
The regulator of natural gas activities in B.C. is the British Columbia Oil and Gas Commission
(BC OGC). Reclamation of gas facilities in B.C. is described as "the process of restoring the
natural environment to acceptable condition, as near as reasonable to conditions that existed prior
to development" (BC OGC 2011 p 1). Reclamation guidelines for industrially disturbed sites are
governed by the BC OGC for issuing reclamation certification. The regulator has requirements
for operators that stipulate general vegetative requirements under the "Schedule B Site
Reclamation Requirements'' (BC OGC 2013) regarding density, species composition and percent
cover; Schedule B requirements relate specifically to lands within the Agricultural Land Reserve
(ALR). Information about plant species use is not specified in forested lands outside the ALR.
The BC OGC stipulates that land be restored to an equivalent condition following pipeline
installation; however, there is no minimum replacement depth (MRD) of surface soil on linear
disturbances (BC OGC 201 3). Topsoil salvage is required, although for soils with A horizons
less than l 0 centimetres deep, no minimum depth is required in forested lands.

23

2.4.2 Goals ofReclamation
There are two overarching principles guiding reclamation options for a given site, which include
prescriptive planting operations, and natural regeneration strategies. The strategy employed at a
given site may be detetmined by the desired or mandated reclamation outcome, or the capacity of
a site to regenerate naturally (Rayfield eta/. 2005; Gartner eta!. 2011; Roll and Aide 2011). A
study of a degraded ecosystem examined simple and complex restoration strategies found that
moderate complexity of restoration efforts determined plant community recovery (Rayfield et a!.
2005). The complexity of reclamation strategies may be dependent on site specific conditions,
where the level of site degradation and environmental variables correlate with the intensity of
site management necessary to promote forest rehabilitation (Stan turf and Madsen 2002; Blanco
and Lal 2008; Chazdon 2008).
2.4.3 Plants
When replanting strategies are chosen in a reclamation program, practitioners should decide on
the species to employ. Historically, planting programs in reclamation have been haphazard
regarding plant types, and forest tree species were used according to silviculture practices and
timber values (Kelty 2006; Groninger eta/. 2007). There has been increasing attention given to
emulating native species specific to a disturbed ecosystem. Using native plant species in
reclamation helps restore ecosystem functions of a site, and aids in recovery of ecosystem
integtity (Chazdon 2008). Identifying key native plant species can be achieved by reference sites,
and pre disturbance inventories (Koch 2007). Plant species used in reclamation projects should
include mixtures of successional species that include understory and canopy seedlings to enhance
species diversity in degraded forest ecosystems (Sayer eta/. 2004).

24

2.4.4 Amendments
When soils are disturbed by industrial activities, storage of topsoils during the construction phase
can lead to nutrient leaching, and low nutrient values are challenging to successful establishment
for either natural revegetation or planted seedlings. Two options for enabling improved microsite
conditions for spontaneous regeneration of plants, and better field performance of planted
seedlings, include the amendments of fertilizer and unused plant materials such as coarse woody
debris (Jacobs and Timmer 2005). Fertilizer amendments are frequently used to increase major
nutrients, such as nitrogen, phosphorous, and potassium, to planted tree seedl ings for
reforestation (Thirukkumaran and Parkinson 2000). Nitrogen, phosphorus and potassium ratios
can vary according to ecosystem needs, however a nitrogen component is usually included
because of its essential role in plant development (Brady and Wei! 2008).
Fallen trees and branches are part of natural processes and plant responses to natural disturbance
events in forest ecosystems; this component of a functioning ecosystem can be simulated by
deployment of unused plant matter, or coarse woody debris, in forest reclamation. Coarse woody
debris (CWD) creates rnicrosites, and enhances soil physical properties and plant seedling
establishment in boreal forest stands (Takahashi eta/. 2000). Coarse woody debris can be used
for reclamation purposes and may be a key factor of successful reclamation in forest ecosystems
(Brassard and Chen 2008; Vinge and Pyper 20 12). Its use in reclamation bas been paralleled with
its role within intact forest ecosystems for enhancing soil physical properties, and improved plant
establishment (Brown and Naeth 2014). To improve site conditions for reclamation, CWD
should be left at the harvest site, enhancing nursing environments for young seedlings,
stabilizing of soil pH, and mitigating erosion potential (Brown and Naeth 2014; Kappes et af.
2007; MacKenzie 201 I).

25

2.4.5 Soil P rop erties
Soils are key foundations to forests, and soil health is a critical component of forest development
(Brady and Weil2008). Soil properties are indicators of forest ecosystem health; properties such
as physical and chemical properties are intenelated, and the interplay between soils and
vegetation form a nutrient feedback cycle (Doran and Ziess 2000). Human activities have altered
elements of this relationship through intensive forest practices and subsurface disturbances that
displace soil horizons (Ballard 2000). Due to industrial disturbance, soil quality and integrity
following disturbance can be impacted by industrial development (Piirainen eta!. 2007;
McConkey et a!. 20 12; Reeves et al. 20 12), and legacy soil quality in tum affects plant growth
and survival (Fisher and Binkley 2000; Knoepp et al. 2000; Schoenholtz et al. 2000). The soil
properties affected depends on disturbance type, such as pipeline construction, which involves
whole tree harvest, potential removal of litter horizons, and disturbance of A, B, and C horizons
in mineral soils, and 0 horizons in organic soils (Landsburg 1989; Desserud et al. 2010). In
some cases, disturbance of parent materials can alter the pH of mineral soils if lower and upper
substrates are mixed during the disturbance process (Hammermeister eta!. 2003; McConkey et

al. 2012).
Mixing of soil horizons during disturbance and in preparation for replanting (Naeth eta/. 1987;
Thiffault eta!. 2011 ; Zummo and Friedland 2011) can impact site and soil quality. Tllis
disturbance can vary in consequence for the recovery of vegetation, although evidence is sparse
(Maynard eta!. 20 14) for either concept. Some research suggests that mixing soils can enhance
growing conditions for some plant species such as lodgepole pine, which can access soil
nutrients exposed through soil mixing (Ballard 1980; Campbell et al. 2006; Thiffault et al.
2011).

26

Soil chemical prope11ies affect the performance of planted seedlings, as well as natural
regeneration of a disturbed ecosystem (Jurgensen eta!. 1997; Schoenholtz eta!. 2000). Values of
soil nutrients such as N, Sand P can be altered (Coiffait-Gombault et al. 201 1) if existing
organic matter is lost through whole tree removal and burning of forest floor material (Ballard
2000). In many instances, some nutrients can be made available to plants through disturbance,
although nitrogen requires atmospheric or biotic input (Ballard 1980). Litterfall is a significant
step in nutrient cycling; nutrients return to the forest floor in organic form, where mineralization
makes them available to plants (Huang and Schoenau 1997). A meta-analysis of the removal of
harvest residues found a sl ight decrease in nitrogen, whereas leaving residue showed an increase
in total nitrogen in forest soils. Depending on harvest type and plant species, saw log harvest left
more residues on site and increased soil Nand soil C, while whole tree removal left little harvest
residues, which reduced soil nutrient retention (Johnson and Curtis 2001).
Soil bulk density is an indicator of soil compaction, and is relative to soil class (soil texture).
Different thresholds for what determines a compacted soil to the extent it can influence plant
growth depends on soil texture and soil moisture; for example, high soil moisture means a fine
textured soil is more prone to compaction by human activities (Berli et al. 2004; Campbell et a!.
2008). Soil compaction can have long-term effects on soil productjvity, and is attributed to lower
growth rates of plants in agricultural and forest soils (Conlin and van den Driessche 1996; Grigal
2000; Spoor 2006). Most effects of heavy equipment on soil bulk density occur when soils are
relatively wetter, and within the ftrst few passes over the same area by harvesting and
construction equipment (Lovich and Bainbridge, 1999; Lee and Boutin, 2006). Some research
has shown high bulk density for a given soil class to be a factor for reduced biomass, reduced
root-shoot ratios, and reduced plant survival in lodgepole pine seedlings (Corns 1988), therefore

27

activities should take place when compaction is less likely, such as winter or late summer in
cold, dry ecosystems on these soils.
Soil pH refers to acidity or alkalinity of a soil, and it influences the survival and growth of plants,
potentially more so during pipeline reclamation. Many plant species have a preferred pH range,
and unsuitable pH can affect establishment and growth of some plant species (Hartel, 1999).
Industrial disturbance may alter soil pH, for example mixing surface horizons with subsoil
material rich in carbonates (Hammermeister et a/. 2003); but some disturbed forest soils may not
always exhibit changes in soil chemical properties due to industrial disturbance (McConkey et al.
20 12). This may be a site-specific factor, as research regarding pipeline installations found that
chemical properties of some soil types are altered differentially by disturbance (Naeth eta/.
1987).
Soil temperature changes following industrial disturbance due to increased exposure to solar
radiation and the condition of surface organic horizons (Stathers and Spittlehouse 1990).
Industrial disturbance can affect the range of soil temperature due to whole tree removal (Hayhoe
and Tarnocai 1993; Mariani et al. 2006). Soil temperatures can impact the regrowth of certain
plant species in cold regions such as those found at high elevations and latitudes (McConkey et

al. 20 12). In some ecosystems, increased soil temperature may slightly extend growing seasons
at more northern latitudes (Way and Oren 2011). As some plants are more tolerant of wide
temperature variances throughout a growing season, the consequences of soil temperature effects
on plant growth are site- and species-specific (Hayhoe and Tarnocai 1993; Schulze et al. 2005).
Soil moisture is another variable that may be influenced by industrial disturbance. Soil moisture
is a critical component of plant growth; it influences species establishment in plant community

28

'
development and rates of soil respiration (Raich and Tufekcioglu 2000; Ehrenfeld eta!. 2005).
Ground-based industrial activity impacts the water retention and porosity of a soil, therefore the
ongoing use of pipeline right-of-ways for maintenance and travel can impact right-of-way soil
moisture (Naeth et al. 1987; Lovich and Bainbridge, 1999; Lee and Boutin, 2006). Research
from northeastern BC (McConkey eta/. 2012) suggested that treatments applied to soils affected
water holding capacity of soils during summer months.
Soil carbon content and soil nutrient availability to plants can be altered due to underground
pipeline installation (Soon eta/. 2000a). Soi l nutrients are important to achieving a reliable
method for detem1ining effects of substrate distmbance (Schoenholtz et al. 2000). Confounding
effects of substrate disturbance may occur between physical and chemical properties of disturbed
soils (Coiffait-Gombault 2011; Soon et a/. 2000b; Naeth et al. 1987), as soil disturbance can
expose minerals and nutrients that would otherwise be unavailable to plant seedlings (Naeth et

a/. 1987; Piirainen et al. 2007). In many ecosystems, industrial activities have increased the
availability and abundance of nutrients such as nitrogen, but reduced that of other nutrients
(Evans and Belnap 1999; Frey et al. 2003). ln instances where substrate disturbance has altered
soil pH, soluble phosphorus can be reduced (Soon eta/. 2000a).

2.4.6 Topography
Slope is a component of soil phase, defined as a functiona l unit that varies according to the
classification of soil taxa (Agriculture and Agri-Food Canada, 20 10). The steepness of a slope,
combined with soil texture, determines slope stability when vegetation is removed (Withers
1999; Reubens eta!. 2007). Mechanical weathering and erosion move topsoil downslope, which
can negatively impact plant growth at the upper elevations of a slope and smother seedlings at
lower slope positions. Stability of some aggregates has been linked to the susceptibility of topsoil
29

for erosion and is further influenced by particle size and distribution (Barthes and Roose 2002).
Aggregate stability determines resistance of topsoil to slaking, which is caused by air that
becomes compressed within rapidly wetted soil aggregates. Steeper gradients are subject to
increases in overland flow of water, and water stress to plants growing on a slope is greater than
areas with little slope. Topography can also influence plant species diversity at a site with
moderate to steep slopes (Pareliussen et al. 2005; Zinko et al. 2005).
Slope aspect determines the amount of sunlight and other envirorunental factors to which plants
and soils are exposed. At high latitudes in B.C., seasonal changes in sunlight mean daily sunlight
exposure varies between seventeen hours in June, to six hours in December. Astrom et al. (2007)
documented that soils on north-facing slopes in the Northern Hemisphere are wetter and cooler
than south-facing slope soils, due to a lower amount of solar radiation. Under certain
circumstances, even in period of long daylight hours, sun exposure can be minimal. South-facing
slopes in North America receive a greater amount of solar radiation than north-facing slopes
(Warren II 2010). The soils on south-facing slopes warm faster, and may suffer greater losses of
water through evaporation than north-facing slopes. Conversely, as they receive greater amounts
of sunlight, plants on south-facing slopes begin annual growth sooner than plants on north facing
slopes.
As aspect determines light exposme and moisture retention, different plant species may be
present according to their adaptability and suitability to low or high light exposure (Schulze et al.
2005). Plant species that respond to high light conditions, such as lodgepole pine, may exhibit
stronger growth on south facing slopes at high latitudes. A study from northern B.C. found
increased growth rates oflodgepole pine seedlings in response to high light conditions in a
boreal forest region (Wright et al. 1998), and that light was more strongly correlated to plant
30

growth than regional climatic conditions for lodgepole pine (Wright et al. 1998). High light
conditions may be a feature of tree harvest where opening a dense forest canopy allows for
greater light penetration to the forest floor, and coupled with aspect of a gradient that dictates
exposure to sunlight.
High elevation can be limiting to plant growth. Plant species growing at high elevations
experience low soil nutrients, moisture deficits which are also related to slope percentage,
persistent freezing temperatures for ambient and belowground conditions, and persistent high
winds (Korner 1998; Cano et al. 2002; Lloyd and Fastie 2002). High elevation mountainous soils
are often poorly developed with thin to variable organic layers, which combined with low
temperatures, leads to lower rates of nutrient cycling (Rowell 20 l 0).
Erosion includes the transportation and deposition of organic matter and certain soil particle
sizes may result when pipeline construction results in changes in topography. In areas subject to
high displacement of soil through wind erosion, even sparse vegetation can mitigate some effects
of mechanical erosion (Wolfe and Nickling 1993). Coarse woody debris is another mitigation
measure for reducing erosion. Its role has been extensively studied in riparian ecosystems
(Gregory eta/. 1991; Lee eta/. 2004), and has been successfully used for erosion control in
upland ecosystems (Bobiec 2002; Vinge and Pyper 2012). Coarse woody debris may be naturally
sourced from windthrown trees, from local trees not deemed desirable lumber species, or be
placed strategically for structured intervention for forest management (Keddy and Drummond
1996; Robertson and Bowser 1999). Its roles in upland forest ecosystems include erosion control,
seedling shelter from mechanical effects like wind, and from biotic effects such as trampling
(Brown eta/. 2003) by wildlife.

31

3.0 Ojay Study Site
The site for this study was located in the south Peace region of B.C., east of the Rocky Mountain
range, approximately 40 km west of the Alberta border and 70 km southeast ofTumbler Ridge
B.C. (Figure 2). The pipeline right-of-way was established in 2007 in an area leased by Shell
Canada and was part of a natural gas transmission line within the Deep Basin North natural gas
reserve of the Western Canadian Sedimentary Basin. The 21 km Ojay pipeline was established
by Shell Canada to transmit sweet gas from seven well heads to a collection station in
northwestern Alberta (Sherrington, pers. comm. 2012) during the winter of2007-2008.

The installation of the pipeline included clearing of an 18 m right-of-way in a mature forest stand
to facilitate access of equipment for construction and backfill operations. For the construction of
the pipeline, one side of the trench was cleared for vehicle and machinery access to the trench for
excavation and installation of pipe; and the other side of the trench contained separate mounds of
A horizon soils, laid closest to forest edge, and B and C horizons, laid next to the trench. The one
exception was the ESSF 4 block, where only the trench area itself was disturbed. Trees in this
block were removed at an earlier date for the establishment of a winter industrial access road,
and not part of the harvest for the pipeline right-of-way.

32

British Columbia
Ojay Pipeline research sites
.loawson Creek
• Turhbler Ridge

N

_....
Figure 2. Location map ofOjay study site in northeastern British Columbia.

The study area consisted of sampling uruts, defined for this study as "blocks". The research
blocks were established by Shell Canada. Eight blocks in total were established (Table 1), which
included four in the BWBS zone and four in the ESSF zone. Blocks were numbered according to
slope and aspect positions; number one blocks were established on south-facing slopes, number
two at a hill crest, number three on north facing slopes, and number four in wetlands. Forest
types at the edge of the right-of-ways were upland coniferous, with lodgepole pine as the
dominant canopy species (except the BWBS north-facing block, which was mixedwood), and
wetland blocks were lowland coniferous. The ESSF 1 (south-facing) and ESSF 3 (north-facing)
33

blocks had relatively steep slopes, and both mid-slope blocks which were on opposite sides of
the same hill.

Slope aspect within the research area varied mostly between north and south, incorporating the
direction of the pipeline. There were conditions where for example, BWBS 2, although
designated a crest position, had a five percent slope with a west aspect. Blocks ESSF 1 and ESSF
3 were mid-slope sites; ESSF I had a south-east aspect and ESSF 3 had a north-east aspect. The
two north-facing blocks (B WBS 3 and ESSF 3) were given a CWD amendment, from logs not
salvaged or burned, to mitigate erosion potential (Figure 3). The arrangement of logs in the
BWBS 3 block was uniform and perpendicular to the slope. and incorporated at a high density.
The CWO used in the ESSF 3 block was arranged randomly and employed a much lower density
than at the BWBS 3 block (Figure 3).

Figure 3. Coarse woody debris (CWO) applications in the BWBS 3 and ESSF 3 north facing blocks (M. Sherrington
photos).

34

Table I. Location, elevation, forest ~Ee and dominant canoe~ seecies at Oja~ research blocks.
Latitude
Longitude
Elevation (m.a.s.l.) Forest Type**
Zone
Block*

Dominant Canopy Species

BWBS

I

54"43' 58.9"N

120" II' 14.8"W

1202

Conifer

Lodgepole pine

BWBS

2

54· 44' 0.2"N

120" II' 12.8"\V

1226

Conifer

Lodgepole pine

BWBS

3

54" 44' 2.1 "N

120" 11' IO.I"W

1212

Mixedwood

Lodgepole pine, balsam poplar

BWBS

4

54· 45' 23.2"N

120" 12' 59.7"W

1225

Conifer

Black spruce

ESSF'

I

54· 42' 57" N

120" 6' 8.0"W

1350

Conifer

Lodgepole pine

ESSF

2

54· 43' 21.6"N

120" 5' 26.2"W

1369

Conifer

Lodgepole pine

ESSF

3

54"42' 26.1"N

120" 6' 57.2"W

1360

Conifer

Lodgepole pine

ESSF'

4

54"43' 25.8"N

120" 5' 17.7"W

1262

Conifer

Black spruce, tamarack

BWBS = Boreal White Black Spruce
ESSF = Engelmann Spruce Subalpine Fir
*Block designation:
I - South-facing block
2 - Crest block
3 - North-facing block with CWO amendment
4 - Wetland block
••Forest type (Penner 2008):
Conifer: > 80% softwood
Mixedwood: 26-75% softwood

35

All research blocks were adjacent to mature forest stands (Table 1). At the BWBS l and 2
blocks, and the ESSF upland blocks. upland conifer stands were dominated by lodgepole pine.
The BWBS 3 block was a mixedwood stand, and the wetland blocks were conifer dominated.

:,.unpk Blocl La~ou1

Control
plots

.-~ =h-,
[b'
c::knl.j_
~ - :an

Pine ~

plots

~

T

1

J

~s

__

~

~
1

1

r- 1

Cinquefoil plots

Pine
plots

Figure 4 . Sample block layout showing pipe trench (green rectangular box) and plot locations within block
boundaries.

Permanent plots were marked for the study, based on the original plot sizes determined in the
layout established by Shell Canada and Reclaimit Ltd. (Figure 4), marked by wood stakes. Block
sizes were I 8 m x 37 m, except in the BWBS 4 block, where the encroachment of a winter
access road reduced the block width to 15 m. Within the block boundaries, four strips were
arranged for plant trials, each was 2 m wide and the width of the block boundary ( 18 m, except
BWBS 4). Within the strips, 2m x 2m (4m2) permanent plots were established, however, the
area over the pipe trench, the width of a digging bucket (9 14 mm) (Pedram and Sherrington,
pers. comm. 20 12) was sporadi cally planted with shrub and forb species not considered in this
study. In tlus study, control strips, which consisted of unplanted areas, were established by Shell

36

Canada. In 2012, unplanted control plots were created within the previously established control
strips to dete1mine extent of natural regeneration of plant species for the study period.

In the summer of2010, Reclaimit Ltd. planted 4 tree species, 11 shrub species, and 2 forb
species (see Appendix 2 for species list and planting numbers) in the plots. Plant seedlings were
one-year-old at time of planting, and were propagated by Sylvan Vale Nursery in Black Creek,
B.C. Species selected for planting were based on soil moisture regime tolerance, and tree
seedlings were planted as far as practicable from the pipe trench. Fertilizer pouches (N:P:K ratio
25:0:0) were added to holes dug for lodgepole pine seedlings in upland blocks at the time of
planting; shrub and forb seedlings did not receive fertilizer treatment at planting.
Treatments for the purpose of this study were defined as plots planted with either lodgepole pine

(Pinus contorta) or shrubby cinquefoil (Dasiphorafruticosa). Upland blocks had eight pine plots
and three cinquefoil plots each; planting densities for pine ranged between 10-20 individuals, and
between 50-100 individuals for cinquefoil within each plot. Wetland blocks had four pine plots
per block, BWBS 4 had two cinquefoil plots, and ESSF 4 had three cinquefoil plots. Some plant
species were common to all eight blocks (e.g. lodgepole pine and shrubby cinquefoil), while
others (e.g., white spruce (Picea glauca), black spruce (Picea mariana), mountain avens (Dryas

octopetala) and tamarack (Larix laricina)) were only present in blocks associated with preferred
soil moisture regimes for the species.

37

4.0 Soil Properties and Topographic Features on a Reclaimed Pipeline Right-Of-Way in
Northeastern British Columbia
Abstract
Soil properties can determine the establishment and growth of plants, and are often altered by
industrial development. The objective of this study was to determine soil properties and
topography on a reclaimed natural gas pipeline right-of-way in northeastern B.C. Soil properties
analysed included in situ moisture content, cation exchange capacity (CEC) (and exchangeable
cations), particle size distribution, total C, and major nutrient content including total N, S, and
available P. Separate soil samples were taken in June 2013 and analysed for pH and bulk density.
Analyses showed variable soil moisture, nutrients, and cation exchange capacity between the
upland blocks. The soil properties analysed in this study were influenced by presence or absence
of organic horizons in mineral soils; soil nutrients, soil C, and CEC were high in organic wetland
soils. This study found variability in soil properties related to slope aspect, which could impact
reclamation decisions in northeastem B.C.

38

4.1 Introduction
The resource extraction industry in western Canada has become the backbone of Canada's
economy. Natural gas rese1ves in northeastern B.C. contributed to approximately 27% of total
marketable Canadian natural gas production in 2014 (NEB 20 15). A number of alternatives exist
for the transport of natural gas, and transport via underground pipelines is a common option. As
more pipelines are proposed and constructed, there is a need to understand the impacts of rightof-way clearing and soil horizon disturbance on forest soils, to provide background information
for developing refined strategies for the reclamation of pipeline rights-of-way.
Right-of-way clearing for a pipeline involves whole tree harvest, and soil horizon disturbance
through trench construction (Desserud eta/. 20 I 0). Following pipe insta llation, the trenches are
backfilled with stored soils, and prepared for reclamation. Mechanical site preparation is the
practice of recontouring a harvested area for planting, using heavy equipment to decompact soils,
remove unwanted woody debris, and sometimes to create microsites to faci litate plant
establishment (Bulmer and Krzic 2003; LOf eta/. 20 12). It is commonly used to promote faster
regrowth of forest stands (Schmidt eta!. 1996). Some research has found that increasing severity
(windrowing and burning) and complexity of site preparation techniques (fe11ilization plus tree
seedling planting) was associated with improved performance of conifers in reforestation of
industrially disturbed sites in interior B.C., and Sudbury, Ontario (Haeussler eta/. 1999; Rayfield

eta!. 2005).
Although the impacts on soils by forest practices are generally well understood, the
repercussions to soils from underground pipeline installation in northeastern B.C. are less well
known. Pipeline infrastructure installations change soil horizons, can remove organic matter and
may alter slope stability in mountainous terrain (Naeth eta/. 1987; Piirainen eta!. 2007;

39

Thiffault eta!. 2011; Zummo and Friedland 2011; McConkey et al. 20 12; Olson and Doherty
20 12; Reeves et al. 20 12), therefore it is critical to better encapsulate the effects of linear forest
fragmentation, whole tree removal, and soil horizon disturbance related to pipeline installations.
This study was conducted to understand the impacts to soils, plant communities, and field
performance of planted seedlings by right-of-way clearing and pipe trench consnuction for
natural gas transfer infrastructure. The objective of this study was to examine soil chemical and
physical properties, and topographic features present on a reclaimed natural gas pipeline right-ofway in northeastern B.C. This primary objective was to improve knowledge of what roles soils
play in plant community recovery and plant growth and survival at a pipeline Iight-of-way
reclamation project in the Boreal White and Black Spruce wet cool biogeoclimatic subzone
(DeLong et a!. 1991) and Engelmann Spruce - Subalpine Fir moist very cold biogeoclimatic
subzone (Coupe et al. 1991) in northeastern B.C.

4.2 Materials and Methods
4.2.1 Study Site and Experimental Design
The study site was located in the south Peace region of northeastern B.C., on the eastern slopes
of the Rocky Mountain range, 40 km west of the Alberta border. The study area was subject to
logging for right-of-way establishment in 2007, except the area including the ESSF 4 block,
which was harvested in 2004 for winter road construction. The pipeline right-of-way was
established in 2007 at an asset leased by Shell Canada (see Chapter 3 for site details). The
dominant soil type in the research area was the Luvisolic order (Luvisols and Gray Luvisols were
noted at the site). Site soil moisture and nutrient regimes were originally repOiied by Shell
Canada environmental staff in 2007, and confirmed by the UNBC research team (Table 2) in
2012.
40

Table 2. Soil moisture and nutrient regimes for each block.
Biogeoclimatic Zone

Block no.*

Soi l Moisture

Soil Nutrient Regime

Mesic

Medium

BWBS
BWBS

2

Submesic

Poor-Medium

BWBS

3

Subhygric

Rich

BWBS

4

ESSF

Hydric

Medium

Submesic

Low

ESSF

2

Subxeric

Poor

ESSF

3

Submesic

Medium-Rich

Hydric

Medium

ESSF
4
BWBS- Boreal White and Black Spruce
ESSF- Engelmann Spruce- Subalpine Fir
*Block description
1 -South-facing block
2 - Crest block
3 - North-facing block with CWO amendment
4- Wetland block

4.2.2 Sampling and Data Collection

At each of the six upland blocks, eight pine plots and three cinquefoil plots were established in
2010 (see Chapter 3 for more details on block establishment by Shell Canada). In the two
wetland blocks, four pine plots were created; in BWBS 4, two cinquefoil plots were created, and
three cinquefoil plots were made in ESSF 4. In this study, treatment referred to unplanted
controls, and plots planted with lodgepole pine (fertilized at planting in upland blocks), and
shrubby cinquefoil.
A total of three hundred soil samples (two samples were taken from each plot for control, pine
and cinquefoil plots) were taken for chemical and physical properties in August 2012, and
consolidated for each plot (n = 150, see Table 3). The samples were stored in a cooler at 4°C,
then air dried at ambient air temperatures, and re-weighed (450 g each). The mineral soil samples
were sifted through a 2 mm sieve to remove large particles and organic debris. These samples
were used for pH, particle size analysis, nitrogen, carbon, sulphur, phosphorus, and cation

41

exchange capacity (CEC). Core samples were taken for bulk density calculations. All results
were expressed on an oven-dry equivalent basis.
Table 3. Number of soil sameles taken from each elot, block and biogeoclimatic zone in 2012.
Treatments
Biogeoclimatic zone
BWBS

Block
I

Control
9

Pine

BWBS

2

9
9

BWBS

3

BWBS

4

ESSF

I

ESSF

2

9
9
9

ESSF

3
4

9
9

ESSF

Cinguefoil
3

Soil sameles eer block
20

8
8

3

20

3

20

3*

2**

14

8
8

3

20

3

20

8

3

20

4

3

16

8

Total
BWBS - Boreal White and Black Spruce
ESSF - Engelmann Spruce - Subalpine Fir
*One pine plot disregarded due to human interference in BWBS 4
** Two plots planted with cinquefoil in BWBS 4

150

4.2.2.1 Soil Pits
Soil pits were dug in 20 13 to understand the physical features found within the area disturbed for
right-of-way clearance and construction. The components of soils considered in this study were
adapted from the Land Management handbook 25 (BC MoFR and MoE 2010) Soil Descriptions
chapter. One soil pit was dug on the right-of-way at each block, and one pit was dug in the forest
adjacent to the right-of-way block. Data were recorded for organic horizons, humus type, soil
horizon depth (A, B, and C), soil texture, and drainage.

4.2.2.2 Soil Moisture
Volumetric soil moisture readings were taken in 2012 and 2013 growing seasons. Readings were
taken with a portable Delta T soil moisture reader, using a Theta Probe (type ML2x), at the
surface of mineral soil on the pipeline to a depth of 5 em (probe length). Two readings were
taken from each plot, and an average of the two readings was reported. Fluctuations in wetland
42

water tables were documented by way of steel welding rods installed along a transect in the
BWBS 4 and ESSF 4 wetland blocks to track seasonal fluctuations in moisture levels (Bridgham

et al. 1991; Silins and Rothwell 1999). The range of oxidation obsetved along the welding rods
was measured, and measurements were used to detennine the range of fluctuation of water tables
in the wetland blocks over the growing season.

In February 2013 , snow depth in all blocks was measured to understand the potential that snow
cont:ti butes to soil moisture in early summer. Two rows were laid out in 25 m length transects,
spaced 5 m inside from block boundaries. Snow depth was measured with a snow probe every 1
m along each transect (n = 50 per block), along with recordings as to whether the soil beneath the
snow pack was frozen or unfrozen.

4.2.2.3 Soil Temperature
Soil temperature was taken in the second year of field sampling. Eight HOBO dataloggers (one
datalogger per block) were installed outside the block boundaries. One temperature probe was
installed at a depth of I 0 em on the pipeline right-of-way within the block boundary and one
probe was installed at a depth of 10 em in the adjacent forest. Readings were logged every two
hours from June 2013 unti l October 2013.

4.2.2.4 Bulk Density
One hundred and twenty-eight samples were taken at 0 em (core depth to 6 em) with a slide
hammer (r = 2.7 em, h = 6 em, volume= 137.47 cm 3) at random points in plots within the block
boundaries for control, lodgepole pine, and shrubby cinquefoil plots, and in random points on
right-of-ways and the adjacent forest. For each block, eight samples were taken on pipeline, and
eight were taken from within the forest. One hundred and three samples were used for bulk

43

density calculations; twenty-five samples were disregarded as they could not be accurately
identified. These samples were oven dried at 70°C for fou r days, and re-weighed. Bulk density of
the samples was calculated using the equation: dry weight (g) I soil volume (cm 3).

4.2.2.5 Soil pH
Soil pH was determined using distilled water (dH 20) following methods described by Kalra and
Maynard (1991) in a laboratory at UNBC. For mineral samples, 25 g soil was combined with 50
ml dH20 to achieve a l :2 soil to dH2 0 ratio. For organic samples, 5 g soil was diluted with 50 ml
dH20 for a 1:10 ratio. Samples were stirred intermittently for 30 minutes, and then allowed to
stand for a further 30 minutes. Readings were taken using a Thermo ORION 550 A pH meter,
which was calibrated at 4.0, 7.0, and 10.0 pH levels.

4.2.2.6 Additional Soil Properties, Cation E xchange Capacity, and Texture
Samples from each plot were sent to the B.C. Ministry of Environment Chemistry analysis
laboratories in Victoria B.C., where the analyses for soil C, soil nutrients, cation exchange
capacity (CEC) and particle size analysis were performed. See Appendix l for methods applied
for each analysis.

4.2.2. 7 Topography
Topographic properties of each research block were provided in ground inspection forms by
Shell Canada, and were confirmed by the UNBC research team in 2012. Aspect was verified
with a Suunto™MC-2 NH mirror compass (2012 declination = 18° 14.76' E, NRC 2016), slope
was confmned using a SuuntoTM PM5/360PC clinometer, and elevation was determined by a

GarminT" Dakota®20 global positioning system (GPS).

44

4.2.3 Data Analysis
ln this chapter, the data were not subjected to standard tests for normality or ANOV As, as the
purpose was to characterize soil properties in the research blocks. The results described trends at
the blocks. Statistical relationsrups between soil properties and plants are presented in chapters 5
and 6. Results for soil moisture, bulk density, macronutrients (N, S, P), soil C and CEC were
separated between wetlands and uplands. Topographic variables were reported as whole
numbers. Soil properties were subjected to descriptive statistics, analysed with STATA® 13. 1
(StataCorp LP, College Station, Texas, USA), means and standard errors were reported in the
results.

4.3. Results
Soil pit descriptions are shown for uplands only, as data was not available from the BWBS
wetland block. Results of major nutrients (total N, total S, and available P), soil total C, effective
CEC, soil moisture, and bulk density were separated between uplands and lowlands due to
marked differences in values. Soil class (texture) was recorded in upland blocks only, and results
of the BWBS 3 block were disregarded as the high organic matter content nullified the
usefulness of pa1ticle size results.

4.3.1 Soil Pit Descriptions
Soil physical properties were compared between the right-of-way and the forest to determine
effects of human disturbance. Organic layers (Table 4) for upland soils were shallow on the
right-of-way with the exception ofBWBS 3, and in a few instances, there was no organic layer
present. The BWBS 3 block had the moder humus form on the right-of-way and in the forest,
whereas the BWBS 2 block had mor humus form on the right-of-way and moder humus form in
the forest.

45

Table 4. Soil 2it organic la~er features for right-of-wa~ and forest u2land blocks.
Humus Form
Soil Organic Layer Depth (em)
Right-of-way
Forest
Right-of-way
Forest
Zone
Block
Maximum Minimum Maximum Minimum
NIA
Mor
BWBS
I
0
0
9
7
Mor
Moder
2
I
0
5
3
Moder
Moder
20
3
20
15
36
N/A
Mor
12
ESSF
0
0
9
2
I
NIA
Mor
3
0
0
Mor
Mor
3
0
12
9
Humus forms:
Moder: Some incorporation of litter into mineral soil
Mor: Mat of partly decomposed litter, not well incorporated in mineral soil
N/A: Not Applicable

Humus types from right-of-way samples were mostly fibric, although there was evidence of
decomposition in humus at the BWBS 3 block, where some mesic material was noted. At the
forest pits, humus types were fibric at the BWBS 1 block, while there was mesic material in the
crest and north facing sites. The humus type was fibric at all upland forest pits in the ESSF zone.

Mineral layers in upland blocks varied considerably (Table 5). There were three instances
(BWBS 1, BWBS 2, and ESSF 2) where the A horizon was not discemable from the B horizon.
Where the A horizon was present, it was deeper than the A horizon depths observed in the forest
pits. At BWBS 3, the A horizon depth maximum on the right-of-way was greater than intact
forest soil by 1 em. At ESSF I, the A horizon maximum on the right-of-way was simi lar to the
intact forest soil (difference was l em), and at ESSF 3, the right-of-way A horizon exceeded the
forest soil A horizon by up to 22 em. Depths at which C horizons were observed varied between
blocks, however, highest points of C horizons were observed at a greater depth in the northfacing blocks in each zone than either the south-facing or crest position blocks (Table 5).

46

Table 5. Soil mineral layers for right-of-way and forest sample pits in upland blocks.
Soi l MineraJ Layers
Depth (em) (Right-of-way)
Minimum
Maximum
Suffix* Extent thick11ess
thickness
Suffix
Zone
Block Layer
not discernable
h
BWBS
1
A
28
22
p
t
B
0-28
29+
k
NIA
NIA
k
c
h
2
A
not discernable
32
m
B
p
0-36
36
36 +
N/A
NIA
k
c
k
A
h
0-16
16
12
h
3
41
g
B
hf
17-71
46
71 +
N/A
N/A
c
k
k
19
12
h
ESSF
A
he
0-19
B
m
37
29
m
19-51
51 +
N/A
g
NIA
k
c
not discemable
h
2
A
g
33
B
m
0-35
35
35 +
N/A
k
NIA
k
c
3
A
h
0-40
40
35
h
42
35
g
B
m
41-83
N/A
N/A
k
83 +
k
c
* Suffixes as defined in Soi l Classification Working Group (1998):
g: grey colours or prominent mottling
h: enriched with organic matter
he: natural eluviation with grey shades and sometimes platy structure
hf: more than 5% organic C
k: presence of carbonate
m: slightly aJtered by hydrolysis, oxidation, or solution
p: altered by human activities including pipeline construction
t: illuvial horizon enriched with silicate clay

Depth (em) (Forest)
Maximum
Minimum
thickness
Extent thickness

0-9
10-40
40 +
0-15
16-46
47+
0-15
15-85
85 +
0-18
19-68
68 +
0-15
16-48
48 +
0-18
19-47
47+

9
30
N/A
15
34

NIA

NIA

NIA

15
75
N/A
18
48

12
70
N/A
16
40
N/A
9
27

NIA
15
36
N/A
18
33

NIA

7
20
10
30

NIA
9
29

NIA

Drainage of the upland sites varied according to slope position. Drainage classes were very well
drained in the south-facing blocks and the BWBS 2 block; the ESSF 2 block was rapidly drained.
The drainage class for north-facing blocks were moderately well drained in the ESSF 3 block,
and imperfectly drained in the BWBS 3 block. Soi l pits dug on the right-of-way and in the

47

adjacent forest had ground seep at approximate ly 60 em (Figure 5) in the BWBS 3 block.

Figure 5. BWBS 3 (north-facing block) right-of-way soil pit showing seep at approximately 60 em depth.

4.3.2 Soil Moisture
Soil moisture in upland sites varied between biogeoclimatic zones, slope position, and aspect
(Figure 6). Moisture values in upland blocks were highest in north-facing blocks in each zone.
and lowest in crest position blocks in 2012. There was more so il moisture variability in 2013; in
the BWBS zone, lowest mean values were recorded in the BWBS 1 block, while the BWBS 2
block had the lowest mean moisture content in the ESSF zone. In the wetland blocks, soil
moisture values in BWBS 4 were higher in 20 13, while ESSF 4 block content was higher in 2012
(Figure 7). Results from oxidation range on welding rods in the wetland blocks found a 9.5 em
average moisture f1 uctuation for the 20 13 growing season.

48

45.00
40.00

tt

35.00
,-..

~
... 30.00

=
c

~

25.00

0

""'~ 20.00
2

rf

1n

I

!

"' 15.00
·c;
~

• 2012
• 2013

10.00
5.00
0.00 fBWBS I

BWBS 2

ESSF I
ESSF 2
BWBS3
Upland block designation

ESSF 3

Figure 6. Mean soil moisture with standard error in upland blocks for 2012 and 2013. n = 20 per block.
140.00
120.00
~ 100.00

I

0
.._,

...=

... 80.00
~

=
0

• 20 12

""'t..
60.00
2
·c;"'
~

~

• 2013

40.00
20.00
0.00
ESSF4

BWBS4

Wetland block designation

Figure 7. Mean soil moisture with standard error in wetland blocks for 2012 and 2013 growing seasons. n = 14 for
BWBS 4 ; n = 16 for ESSF 4.

49

80

70
60
,......
8 50

~

.c

Q.
40
Q,l
"0

.:.:
~

c.
:t:

30

~ 20

00

10
0

-10

BWBS 1 BWBS 2 BWBS 3 BWBS 4 ESSF l

ESSF 2

ESSF 3

ESSF 4

Block Designation
Figure 8. Mean snowpack depth with standard error, winter 2012-2013. (n =50 per block).

Snowpack measurements taken in February 2013 showed greatest depths at the ESSF 4 block,
with an average of 67.7 em between two transects (Figure 8). For the BWBS 4 block, average
snow depth was 54.9 em. ESSF blocks 1 and 2 had the least snow cover, the ESSF 1 block held
6.3 em of average snow cover, and ESSF 2 held 13.8 em of snow. Soils were frozen in southfacing, crest, and north-facing blocks in both biogeoclimatic zones. In the wetland blocks, there
was a frost layer underneath the snow, however, the soils below the frost layer were unfrozen.
There were no weather stations in close proximity to the study site to make comparisons at the
block or biogeoclimatic zone level.
4.3.3 Soil Bulk Density
Bulk density values were variable at upland blocks (Figure 9) and the differences between rightof-way and forest bulk density values were inconsistent. Bulk density within the BWBS 1 block
was the highest (1.33 g cm-3) in the BWBS biogeoclimatic zone, and greatest of all upland

50

blocks, while the ESSF 3 block right-of-way bulk density value (1.24 g cm-3) was highest for the
ESSF zone. Bulk density was slightly higher on the right-of-way for all BWBS blocks. This
pattern for bulk density was not replicated in the ESSF zone, as samples from the right-of-way
had lower bulk density values than those taken from the forest in the ESSF 1 and 2 blocks,
however the ESSF 3 block showed higher bulk density on the right-of-way than for samples
taken from the forest.

• Forest

BWBSl

BWBS2

BWBS3

ESSF 1

ESSF2

ESSF 3

Upland Block Designation
Figure 9. Mean and standard error of bulk density on pipeline right-of-way (ROW) and forest in upland blocks.
Bulk density was taken for the 0 - 15 em range of mineral soils in upland blocks (BWBS 1-3, ESSF 1-3). BWBS 1 n
= 15, BWBS 2 n = 12, BWBS 3 n = 5, ESSF 1 n = 15, ESSF 2 n = 15, ESSF 3 n = 16.

There was high variability ofbulk density within the BWBS 3 block for both the right-of-way
and forest, but otherwise the error of the means showed higher variability for right-of-way
samples than for forest samples in upland blocks. Bulk density values for the BWBS 4 block
were higher on the right-of-way (0. 14 g cm-3) than the forest (0.067 gem-\ while the forest bulk
density (0.22 g cm-3) was higher than the right-of-way (0. 16 g cm-3) bulk density for ESSF 4
block (Figure 10).
51

0.45
0.4
0.35
~

0.3

8<J 0.25
Cl)

;

0.2

~
Q

0.15

.:.=

0.1

jXl

0.05

·a
';

•ROW
• Forest

0+---0.05
-0.1

BWBS4

Wetland Block Designation

Figure 10. Mean and standard error of bulk density on pipeline right-of-way and forest in wetland blocks. Bulk
density was taken for the 0 - 15 em range in organic horizons for wetland blocks (BWBS 4, ESSF 4). BWBS 4 n =
11 , ESSF 4 n = 14.

4.3.4 Soil Temperature
Soil temperature taken within growing seasons at 10 em depth (Figure 11) showed that BWBS
upland blocks had greatest mean temperature at the BWBS 1 block (14.7 oc ± 1.2 °C) and lowest

in the BWBS 3 block (I 3.3 oc ± 1.4 °(). In the ESSF zone, soil temperature average was greatest
in the ESSF 1 block (13.8 oc ± 2.1 °() and lowest in the ESSF 3 block (11.5 oc ± 1.2 °C). The
highest mean temperatures in the ESSF zone were recorded in the ESSF 4 block (14.7 °( ± 1.0
0
(),

whereas the lowest temperature averages in the BWBS zone were observed in the BWBS 4

block (13.3 °( ± 1.0 °().

52

20

18
16

u 14
0

f 12

2<'I
tQ. 10

-~

8

4
2

0
BWBS I

BWBS 2

BWBS 3

BWBS 4

ESSF 1

ESSF 2

ESSF 3

ESSF 4

Block Designation
Figure I I. Mean soil temperature in all blocks in 2013. Temperature taken in the 0-10 em depth range. Averages are
for the growing season (June-August 2013), n = 20 each for upland blocks (BWBS 1-3; ESSF 1-3. For wetland
blocks: BWBS 4 n = 15, ESSF 4 n = 16).

4.3.5 Soil Texture
There was variable particle size distribution between upland blocks from the particle size
analysis conducted on mineral soils (Table 6). Soil class extrapolated from particle percentages
(sand, silt, and clay) was consistent in BWBS 1 for the control, pine, and cinquefoil plots. All
other upland block mineral soils varied between silty loam and loam soils between control, pine,
and cinquefoil plots, however there was no consistent pattern of particle size distribution.
Samples from BWBS 3 were considered invalid due to a greater than 10 % total C content. The
soil classes were more consistent between crest and north-facing blocks, while south-facing
block soil class was of medium texture (loam) in the BWBS zone, while the ESSF zone was fine
to medium (silty loam -loam).

53

Table 6. Particle size (means and standard errors reported in parentheses) for sand, silt and clay with associated soil
class for upland blocks. For each upland block, n = 9 for control plots, n = 8 for pine plots, and n = 3 for cinquefoil
lots.
BWBS1

Control

42.51 ( 4.18)

41.34 (2.45)

16.15 (3 .95)

L

Pine

42.81 (2.74)

41.39 (2.10)

15.80 (1.64)

L

Cinguefoil

43.98 (1.45)

40.74 {1.402

15.28 {0.05)

L

Control

38.40 (4.08)

45.30 (6.03)

16.30 (4.21)

SiL

Pine

35.98 (4.82)

47.00 (5.27)

17.01 (I .32)

SiUL

Cinguefoil

32.09 (0.91)

55.21 (0.912

12.69 (0.00)

SiL

BWBS3

* results invalid
* results invalid
* results invalid

Control
Pine
Cinguefoil

ESSF 1

ESSF2

ESSF3

Silt % {±}

Soil Class*

Treatment

BWBS2

Sand % (±)

Cia~%{±)

Block

N/A
N/A

NI A

Control

37.41 (2.92)

50.01 (2.12)

12.58 (1.43)

SiL

Pine

38.31 (3.49)

49.44 (4.32)

12.25 (1.93)

SiL

Cinguefoil

40.59 (2.17)

46.68 (1.58)

12.73 (1.32)

L

Control

37.19 (3.27)

48.47 (1.90)

14.34 (2.31)

SiUL

Pine

36.80 (3.47)

50.48 (4.18)

12.72 (2.78)

SiL

Cinguefoil

33 .89 {1.25)

52.13 {1.262

13.99 {0.002

SiL

Control

42.35 (6.79)

41.18 (5 .63)

16.47 (2.07)

L

Pine

32.43 (5.12)

50.44 (4.24)

17.13 (2.43)

SiL

Cinguefoil

33.02 {2.832

49.49 (1.39)

17.49 {1.44)

SiUL

* Soil class:
L- Loam
SiL- Silty Loam
SiUL- Silty Loam/Loam
N/A- Not Applicable

4.3.6 Soil pH
Soil pH levels were higher (5.92- 7.41, ± 0.24- 0.83) at BWBS upland sites than ESSF upland
sites (4.62- 4.96, :I: 0.27- 0.48) (Figure 12). Comparatively, average pH in upland blocks was
highest per zone for the south-facing blocks (BWBS 1 and ESSF 1), BWBS 3 exhibited the most
acidic conditions for all treatments in the BWBS zone, while in ESSF upland blocks, pH was
consistently higher in cinquefoil plots than either pine or control plots. Wetland block pH levels
were 6.13 ± 0.28 for the BWBS 4 block, and 6.63 ± 0.27 for the ESSF 4 block (Figure 12), and
pH was higher in pine plots than in cinquefoil or control plots.

54

9

8
7

I

6

I

n:.

dl

~I

~

ri--

fi

• control
• pine
• cinquefoil

3
2

0

......

......

......

BWBS 1 BWBS 2 BWBS 3 BWBS 4 ESSF 1 ESSF 2 ESSF 3 ESSF 4
Block Designation

Figure 12. Mean and standard error of soil pH for control, pine, and cinquefoil plots. For each upland block, control
n = 9, pine n = 8, cinquefoil n = 3. For wetland blocks, BWBS 4, control n = 9, pine n = 3, cinquefoil n = 2; ESSF 4,
control n = 9, pine n = 4, cinquefoil n = 3.

4.3.7 Cation Exchange Capacity
Soil CEC in upland blocks exhibited wide variations within BWBS zone blocks, but more
consistent values in the ESSF upland blocks (Figure 13 and Table 7). BWBS 3 CEC values were
much higher than those observed for BWBS 1 and 2. In BWBS 1 and BWBS 2, plus the ESSF
upland blocks, CEC in the control plots was higher than in pine and cinquefoil plots. This was
not reflected in BWBS 3 results.
CEC values for wetland blocks (Figure 14 and

1

Table 8 8) were similar between the BWBS (control: 171.20 cmol (+) Kg" ± 19.88, pine: 140.57

cmol (+) Kg- 1 ± 8.37, cinquefoil: 186.32 cmol (+) Kg-1 ± 19.69) and ESSF (control: 181.25 cmol
(+) Kg· 1 ± 22.72, pine: 168.46 cmol (+) Kg- 1 ± 20.30, cinquefoil: 138.44 cmol (+) Kg- 1 ± 44.96)
blocks although greater variability was noted in the ESSF cinquefoil samples.
55

120
100
......,
-\:.o
::&::

• control

80

pine

+
.......
0
8u

• cinquefoil

60

'-'

u 40
~
u
20
0
BWBS 1

BWBS 2

ESSF 1
BWBS 3
Block Designation

ESSF 2

ESSF3

Figure 13. Mean and standard error ofCEC (cmol (+) Kg.1) with standard error of upland blocks. For each upland
block, control n = 9, pine n = 8, cinquefoil n = 3.

250

200
......,
-blJ
::&::

£

150
•control

0

8
~ 100

• pine

u

• cinquefoil

tl
50

0
ESSF4

BWBS4

Block Designation
Figure 14. Mean and standard error ofCEC (cmol (+) Kg"1) in wetland blocks. In BWBS 4, control n = 9 pine n = 3
cinquefoil n = 2; in ESSF 4, control n = 9, pine n = 4, cinquefoil n = 3.

56

Table 7. Mean CEC and exchangeable cations (AI, Ca, Fe, K, Mg, M11, Na) and standard error(±) (Cmol (+) Kg"1) of soil in upland blocks. For each upland
block, Control = 9, Pine n = 8, Cinquefoil n = 3.
Block

Treatment

AI

BWBS 1

Control
Pine
Cinquefoil

0.15(0._1])

B WB S 2

BWBS 3

ESSF I

ESSF 2

ESSF 3

Ca

Fe

0.04 (0.08)

16.6(5.04)

0.01 (0.02)

0.06 (0.08)

15.16 {2.87)

0.02 (0.02)

15.49(3.13)

0.04(0.04)

K

Na

CEC

0.004 (0.00 I)

0.02 (0.0 I)

18.47 (5.57)

0.0 I (0.00)

0.02 (0.0 1)

16.80 (3.38)

1.2 1 (0. 17)

0.00(0.00)

0.01(0.01)

17.03(3.40)

Mg

Mn

0.13 (0.03)

1.69 (0.55)

0.12(0.02)

1.43 (0.55)

0.13(0.02)

Control

0. 10 (0.15)

18.36 (7.00)

0.02 (0.03)

0.13 (0.03)

2.36 (1.2 1)

0.01 (0.01)

0.01 (0.00)

21.00 (8.00)

Pine

0.17 (0.15)

13.00 (3.64)

0.03 (0.02)

0.14 (0.03)

2. 12 (0.64)

0.03 (0.03)

0.02 (0.00)

15.51 (3.43)

Cinquefoil

0.22 (0._14)

13.8 1 (8.09)

0.04 (0.0 I )

0.13 (0.05)

2. 10 ( 1.07)

0.02 {0.02)

0.02 (0.00)

16.31 (8.92)

Control

0.05 (0.06)

38.8 1 ( 16.31)

0.0 1(0.02)

0.27 (0.08)

7.16 (3. 11 )

0.06 (0.04)

0.03 (0.0 I)

46.38 (19.40)

Pine

0.03 (0.05)

54.25 (30. 18)

0.0 I (0.0 I)

0.36 (0. 13)

I 0.12 (4.27)

0.09 (0.03)

0.04 (0.0 I)

64.90 (34.49)

Cinquefoil

0.11 (0.09)

5 1.09 (25.16)

0.02 (0.02)

0.33 (0. 19)

8.94 (3.36)

0.07 (0.04)

0.03 (0.0 I )

60.594 (28.65)

Control

1.10(0.95)

5.55(1.49)

0.07(0.06)

0.15(0.02)

3.02(1.19)

0.04(0.03)

0.08(0.15)

10.01 (1.83)

Pine

1.98 ( 1.21)

4. 15 ( 1.85)

0.10 (0.06)

0.15 (0.02)

1.98 (1.31)

0.03 (0.02)

0.02 (0.0 I)

8.42 (1.95)

Cinquefoil

0.54 (0.39)

5.54 ( 1.66)

0.04 (0.0 I )

0.14 (0.02)

3.33 {1.00)

0.03 (0.0 I )

0.02 (0.00)

9.63 (2.29)

Control

2.40 (0.99)

3.92 ( 1.46)

0.11 (0.08)

0.20 (0.07)

1.41 (0.58)

0.06 (0.05)

0.02 (0.0 I)

8.12 (1.68)

Pine

2.15 (0.85)

4.06 ( 1.70)

0.06 (0.02)

0.20 (0.05)

1.39 (0.54)

0.07 (0.03)

0.11 (0.25)

8.04 (1.70)

Cinquefoil

2.52 (0.39)

3.00 (0.22)

0.07 (0.03)

0.19 (0.03)

1.03 (0.08)

0.05 (0.01)

0.02 (0.00)

6.88 (0.44)

Control

0.61 (0.25)

7.39 (0.68)

0.02 (0.0 I)

0.24 (0.06)

2.67 (0.45)

0.05 (0.03)

0.02 (0.00)

11.00 (0.74)

Pine

2.04 (0.76)

6. 10 ( 1.53)

0.04 (0.02)

0.26 (0.05)

2.0 I (0.49)

0.11 (0. 14)

0.01 (0.00)

10.57 (1.44)

Cinquefoil

0.95 (0.65)

6.8 8 (0.81)

0.02 (0.0 I)

0.28 (0.06)

2.39 (0.45)

0.05 (0.0 I)

0.0 I (0.00)

10.58 (0.67)

57

1

Table 8. Means and standard error(±) of exchangeable cations (AI, Ca, Fe, K, Mg, Mn, Na) and effective CEC (Cmol (+) Kg" ) of soil in wetland blocks. For
wetland blocks, BWBS 4: Control = 9, Pine n = 3, Cinguefoil n = 2; ESSF 4: Control n = 9, Pine n = 4, Cinguefoil n = 3.
Block
BWBS4

ESSF 4

Ma

16.88 (1.62)

Mn
0.46 (0.30)

Na
0.15 (0.06)

CEC
171.20 (19.88)

15.11 (0.85)

0.48 (0. 10)

0.17 (0.06)

140.57 (8.37)

0.43 (0. 11 )

17.27 ( 1.92)

0.15 (0.03)

0.1 1 (0.04)

186.32 (22.72)

< 0.00 (0.00)

0.35 (0.16)

18.15 (2.46)

0.12 (0.09)

0.25 (0. 10)

181.25 (22.72)

< 0.00 (0.0 1)
< 0.00 (0.0 1)

0.38 (0.05)

20.07(1.5 1)

0.10 (0.01)

0.32(0.11 )

168.46 (20.30)

0.29 (0.1 8)

16.4 1 (3.34)

0.11 (0.06)

0.18(0.03)

138.44 (44.96)

AI
0.02 (0.00)

Ca
153.15 (18.79)

Fe
< 0.00 (0.00)

K
0.54 (0.20)

Pine

0.03 (0.00)

124.16 (7.82)

< 0.00 (0.00)

0.61 (0.10)

Cinquefoil

0.02 (0.00)

168.35 (17.60)

< 0.00 (0.00)

Control

0.03 (0.02)

162.36 (20.49)

Pine

0.05 (0.05)

147.54(18.89)

C inquefoil

0.04 (0.04)

12 1.42 (4 1.86)

Treatment
Control

58

4.3.8 Macronutrients
Total soil N was higher at wetland sites than upland sites (Table 9 and Table 10). Nitrogen
values in the BWBS 1 and 2 blocks control plots (BWBS 1: 0.115 %, ± 0.039 %, BWBS 2: 0.142
%, ± 0.058 %) in the BWBS zone were higher than for pine (BWBS 1: 0.113 %, ± 0.041 %,
BWBS 2: 0.132%, ± 0.039 %) and cinquefoil (BWBS 1: 0.110%, ± 0.029%, BWBS 2: 0.119
%, ± 0.055 %) plots. In contrast, the BWBS 3 block control plots had the lowest N percentage
compared to planted plots. At the ESSF 1 and 2 blocks, control plots had the highest mean N
values, while the pine plots returned the highest N values in the ESSF north-facing block. In
wetland blockss, theN concentration in BWBS 4 control plots (1.99 %, ± 0.33 %) was slightly
lower than in ESSF 4 control plots (2.13 %, ± 0.43 %).
Table 9. Means and standard error (expressed in parentheses) of major nutrients (nitrogen, sulphur, phosphorous and
Eotassium~ and soil carbon in UEland blocks {n = 20 each block~.
Block
BWBS I

BWBS2

BWBS3

ESSF I

ESSF2

ESSF 3

Total C% {±}

TotalS%{±}

Avail. P mg Kg·• {±}

Treatment
Control

Total N% (±}
0.115 (0.039)

3.92 (0.45)

0.013 (0.005)

1.24 (1.20)

Pine

0.113 (0.041)

4.11 (1.05)

0.0 II (0.007)

1.13 {Ll3)

Cinquefoil

0.110 {0.029}

3.79 {0.43}

0.010 {0.003}

1.29 {1.54}

Control

0.142 (0.058)

4.52 (2.13)

0.018 (0.009)

7.11 (4.28)

Pine

0.132 (0.039)

4.18 (1.27)

0.019 (0.007)

14.01 (9.73)

Cinquefoil

0.119 (0.055)

3.89 (2.17)

0.016 {0.009~

17.21 (6.15}

Control

0.564 (0.322)

13.02 (7.48)

0.048 (0.015)

2.81 (1.34)

Pine

1.092 (0.739)

23.04 {14.06)

0.194 (0.231)

3.90 {1.62)

Cinquefoil

0.902 (0.689}

20.87 (17.00}

0.096 {0.060}

3.28 {1.87}

Control

0.146 (0.024)

3.90 (0.96)

0.017 (0.002)

20.77 (4.47)

Pine

0.133 (0.025)

3.54 (1.01)

0.016 (0.004)

25.45 (12.71)

Cinquefoil

0. 130 (0.034}

3.57 (1.30}

0.017 (0.005}

17.39 (1.01}

Control

0.162 (0.094)

4.27 (3.40)

0.023 (0.0 13)

22.77 (8.93)

Pine

0.157 (0.058)

4.03 (1.99)

0.026 (0.008)

48.51 (32.28)

Cinquefoil

0.114 (0.004}

2.50 (0.092

0.018 (0.003}

24.51 (2.45}

Control

0.196 (0.022)

2.46 (0.78)

0.083 (0.029)

11.75 (3.68)

Pine

0.234 (0.072)

3.30 (1.19)

0.1 02 (0.026)

14.26 (8.03)

Cinquefoil

0.189 {0.019}

2.78 (0.06}

0.113 (0.040}

14.71 (3.672

59

Most upland sites had comparable values of total C, with the exception of the BWBS 3 block
(Table 9). In the BWBS 1 and 2 blocks in the BWBS zone, cinquefoil plots had the lowest total
C, while the control plots had the lowest mean total C in BWBS 3. There was no consistency by
treatment for mean C values in the ESSF upland blocks. Total carbon was high in hydric soils in
both zones (Table 10). Total C in the pine plots was lower than the control or cinquefoil plots,
and lowest C values in the ESSF 4 block were observed in the cinquefoil plots.
Table 10. Mean ru1d standard error (expressed in parentheses) of major nutrients (nitrogen, sulphur, phosphorous and
potassium) and soil carbon in wetland blocks all treatments (BWBS 4 n = I 5, ESSF 4 n = 16).
Block
BWBS4

ESSF4

Treatment
Control
Pine
Cinquefoil
Control
Pine
Cinquefoil

Total N% (±)
2.00 (0.33)
1.75 (0.71)
1.91 (0.18)
2.13 (0.43)
1.66 (0.30)
1.43 (0.63)

Total C % (±)
48.75 (6.00)
40.81 (9.86)
48.74 (3.87)
43.86(5.17)
44.94 (1.66)
39.13 (7.95)

TotalS%(±)
0.262 (0.048)
0.200 (0.058)
0.303 (0.0 16)
0.570 (0.294)
0.339 (0.097)
0.399 (0.324)

Avail. P mg Kg- 1 (±)
3.38 (1.24)
4 .73 (1.41)
1.68 (0.37)
2.84 (2.39)
4.40 (2.96)
4.04 (3.19)

Total S was lower at upland blocks for both BWBS and ESSF zones than at wetland blocks
(Table 9 and Table 10). For upland sites, the north-facing blocks (ESSF 3 and BWBS 3) had
higher values than crest and south-facing slope blocks. At BWBS 3, S percentage was highest for
pine plots and lowest in the control plots. At the ESSF 3 block, highest values were observed at
cinquefoil plots and lowest in the control plots. Wetland totalS was highest in the cinquefoil
plots in both BWBS and ESSF 4 blocks; lowest values were seen in the pine plots at the BWBS
4 block, while the control plots had the lowest mean S values in the ESSF 4 block.
Available P values in mineral soils were higher in the upland ESSF blocks than the BWBS
blocks (Table 9). For the BWBS upland blocks, cinquefoil had the highest amount of available P
in the BWBS 1 and 2 blocks, while the BWBS 3 block values were highest in the pine plots. In
the ESSF 1and 2 blocks, available P was higher in pine (29.40 mg Kg- 1 ± 17.47 mg Kg- 1) plots,
however in ESSF 3, higher P values were found in the cinquefoil plots than for either control or

60

Figure 15. ESSF 3 (nonh-facing block) showing slope failure on left and right sites of right-of-way.

4.4 Discussion
Soil properties observed at the research blocks were variable. Properties were related to slope
aspect of each block, and surrounding forest canopy was related to soil quality. The
incorporation of CWO was benefi cial (see Chapter 3 fo r block design and CWO use) when
applied in high density and situated in close prox imi ty to a mixedwood stand.

4.4.1 BWBS biogeoclimatic zone

Upland soil properties in the BWBS zone were variable and were related to organ ic matter and
forest type. The BWBS I and 2 blocks in this zone were similar in most of the soi l properties
analysed in this study. The BWBS 1 block observed relatively higher soil temperatures, bulk
density, and moisture values (201 3 only). The precipitation and wind experienced at this block
may have contributed to variability in soi l moisture content, which has been linked in other
research (Chen eta/. 1999). The BWBS 2 block had higher nutrients, was more acidic. and had

62

finer soil texture. The higher soil temperatures observed at the BWBS 1 block in this study were
validated by other studies regarding soil temperature on south-facing slopes in the northern
hemisphere (Hayhoe and Tarnocai 1993; Schulze eta!. 2005; Way and Oren 2011). The soil
texture difference between the BWBS 1 and 2 blocks implies that the coarser soil particles may
have moved downslope, which has been observed previously in research that examined soil
particle size and topography (Ampontuah et al. 2006). The soil moisture observations in this
study were similar to other work involving changes in soil moisture by topography (Western et

al. 2004).
The BWBS 3 block was adjacent to a mixedwood stand, and had a high density ofCWD which,
along with the organic matter, may have contributed to the low mean temperature values for the
BWBS zone. The influence of proximity to a mixed wood stand along with high density of CWD
influenced other soil properties, as increased depth of OM has been shown to be correlated with
lower soil temperature and moisture, and translocation of C from leaf litter to soils (Kasischke
and Johnstone 2005; Uselman et al. 2007). High carbon in this block could be attributed to CWD
amendment that potentially buffered winds and allowed for settling of leaf litter. There is also the
potential that some leaf litter was not removed during pipeline construction, however
decomposition was not considered in this study. High soil organic matter content at BWBS 3
also influenced soil bulk density, as values were lower for right-of-way and forest samples in this
block than for other BWBS upland blocks.

Organic matter at the BWBS 3 block was much higher than the BWBS 1 and 2 blocks. The high
organic matter in BWBS 3 contributed to higher total organic carbon, soil nitrogen and CEC
values. The higher nutrient values may be due in part to the proximity of this block to a
mixedwood stand, and the annual senescence from deciduous trees has been correlated with
63

improving soil nutrients in forest soils (Bartels and Chen 20 10) and the CWO density in the
BWBS 3 block may have allowed for improved leaf litter retention, which is supported by other
research that correlated CWD with higher litter retention and soil nutrients at the local scale
(Kappes et al. 2007).

Soil moistw·e values in the BWBS 4 block were more variable in 2012 than 2013 . High total
carbon percentage in this block was consistent with other findings (Fissore et al. 2009) of total
carbon found in peat soils. The BWBS 4 block returned the lowest soil temperature values in the
BWBS zone, which is contrary to the accepted relationship between soil moisture and its ability
to retain heat (Al-Kayssi et al. 1990).

4.4.2 ESSF biogeoclimatic zone
Snow cover measurements showed variability between and within blocks. Exposure to wind was
likely a factor that contributed to snow depth results for the ESSF 1 and 2 blocks, which has been
demonstrated in environments with prevalent winds (Hiemstra eta!. 2002). The variability of
snow pack inferred that rainfall was the precipitation likely to contribute to soil moisture values
during the growing season. Soil moisture was higher in 2013 than 2012, suggesting higher
average rainfall in the 2013 growing season.

Soil bulk density in the ESSF upland blocks exhibited lower values for the ESSF 1 and 2 blocks
than the ESSF 3 block for the right-of-way. The bulk density values for the forest were high at
the ESSF 1 and 2 blocks, and the lowest value observed was in the ESSF 3 block. All bulk
3

density values fell within the suggested ideal range ( < 1.40 g cm ) for the loam and silty loam
soil classes found in the ESSF zone (Daddow and Warrington 1983; Zhao et al. 2010).

64

Soi l temperature was higher in the ESSF 1 and 2 blocks than in the ESSF 3 block; the most
likely reasons were due to the aspect of the ESSF 3 block combined with mature forest canopy
influences on direct solar radiation, as these factors influence the temperature potential of soils at
northern latitudes in the northern hemisphere (Stathers and Spittlehouse 1990; Astrom et al.
2007; Warren II 2010).

Soil nutrients were variable between blocks, although total N and total S were higher in the
ESSF 3 block. As the forest type did not differ between blocks, and as the ESSF 1 block did not
have higher nutrient values than the ESSF 2 block, wind may have influenced the movement of
these nutrients, however this could not be quantified. There was evidence of slash burning along
the right-of-way at the ESSF 1 block, which has been correlated with volatilization ofN and S
(Ballard 2000).

The ESSF 2 block had higher amounts of available P than the mid-slope blocks, although the
mid-slope blocks were on the same hill as the ESSF 2 block. One likely reason was that the A
and B soil horizons were shallower at the ESSF 2 block than the ESSF 1 or 3 blocks, and the
available P was potentially sourced from the parent materials, and therefore closer to the surface
in the ESSF 2 block as a result of soil horizon disturbance during trench construction. The data
from the ESSF 2 block showed a higher amount of available P in the pine plots than either the
control or cinquefoil plots. This was the only block in which high variability between treatments
was observed.

The ESSF 4 block was previously harvested in 2004 for a winter road construction, and was not
harvested for the right-of-way construction in 2007-2008 (see Chapter 3 for site description).
Therefore, this block was disturbed only for the trench digging and pipe installation. The ESSF 4

65

block had adequate major nutrient values, and high CEC. It also had the highest average mean
temperature of all blocks within the ESSF zone, which is consistent with other findings of this
relationship (Davidson eta/. 1998), although this relationship can have confounding seasonal
variability. High CEC values were consistent with the organic matter content of the wetland
block, and high total carbon percentage in the wetland block was consistent with other findings
(Fissore et a!. 2009) of total carbon found in peat soils.

In both biogeoclimatic zones, the 1 and 2 right-of-way blocks had low or no humus layers, and
low amounts of total carbon. The ESSF 3 block also showed low carbon values although there
was CWD amendment. The BWBS 3 block had much higher carbon values, along with high
nitrogen. The placement of CWD in this block was denser than at the ESSF 3 block, however the
BWBS 3 block was adjacent to a mixedwood stand, whereas the ESSF 3 was adjacent to a pure
conifer stand. Soil pits dug both on the right-of-way and in the forest noted differences in A
horizon depth, and mixing of horizons in mineral soils. The differences between the right-of-way
and the forest suggest that current right-of-way construction practices may alter A and B
horizons, and remove organic matter, which contribute to total carbon and soil nitrogen losses
(Prescott 2002).

4.5 Conclusion
The research was conducted to understand the potential impacts to soil chemical and physical
properties of industrial activities in mountainous areas of northeastern B.C. The results showed
that there were differences in soil organic layers and horizon integrity between a pipeline rightof-way and a mature forest stand. Soil carbon and soil nutrient values varied between upland
blocks, and CEC was lower in the ESSF upland blocks than the BWBS upland blocks, likely as a

66

result of low on no leaf litter, and wind effects to litter accumulation, and in the case of available
P, parent material differences.

There were differences related to presence and depth of organic layers between the right-of-way
and intact forest soils. Soil propezty observations in this study noted significant differences in
values between BWBS and ESSF upland blocks. South facing blocks had higher mean
temperatures for upland blocks in both biogeoclimatic zones. In the ESSF zone however, the
ESSF 4 block had highest observed temperature in comparison to upland blocks in the ESSF
zone. There was variable particle size distribution in upland mineral soils. Upland soil pH was
higher in samples from the BWBS zone, indicating more acidic conditions in the ESSF block
soils likely due to geology, dominant canopy species and climate variations.

The observations of variability between blocks in values of soil carbon, soil nutrients and CEC
support retention of organic layers and CWD in mixedwood stands in future reclamation projects
in northeastern B.C. The differences in soil moisture content between the BWBS and ESSF
upland blocks means industry and reclamation practitioners could consider using appropriate
plant species according to soil moisture conditions by biogeoclimatic zone. Other amendments or
site preparation techniques could be considered in pure conifer stands where organic horizons
have not been reserved, are acidic, or have inadequate soil nutrients, and where prevailing winds
may affect plant establishment and field performance.

67

5.0 Plant Species Diversity on a Reclaimed Natural Gas Pipeline Right-of-Way in
Northeastern British Columbia
Abstract

Plant species diversity is an indicator of site health in boreal forest ecosystems. Industrial
disturbances including natural gas pipeline rights-of-way affect the exposure of understory plants
and forest soils to potentially adverse growing conditions through tree harvest and substrate
disturbance. The objective of the study was to determine plant species diversity on a reclaimed
natural gas pipeline in northeastern B.C. Presence and abundance of plant species were recorded
for unplanted controls, planted lodgepole pine (Pinus contorta var. latifolia) and planted shrubby
cinquefoil (Dasiphorafruticosa) research plots. Diversity was calculated with the Shannon
Diversity Index. Species diversity was variable at upland blocks in the Boreal White and Black
Spruce and Engelmann Spruce- Subalpine Fir biogeoclimatic zones; lowest values were
calculated in the crest blocks, and highest values were calculated in wetland blocks. Relatively
low diversity in upland sites may warrant rethinking of plant species used in reclamation
projects.

68

5.1 Introduction
Boreal forests are disturbance-based ecosystems. Human activities, such as natural gas extraction
and transportation, are additive disturbances. The responses of boreal ecosystems to industrial
activities may not replicate responses to natural disturbances (e.g. fire, insect and disease
outbreak, wind damage). More recent human activities such as forestry and other resource (coal,
oil and gas, etc.) development have added to the disturbance footprint, and often replace natural
disturbance regimes, due to forest and infrastructure asset management. Further, industrial
disturbances contribute to soil compaction, increased soil bulk density, poor aeration, altered
moisture drainage and nutrient leaching (Smith eta/. 1999). These and other compounding
factors can affect plant biodiversity (Maestre 2004). Plant species diversity is a culmination of
two components, including the number of individuals of a species (abundance), and the number
of different species (richness) found within a specified area (Whittaker 1972; Huston 1979).
There is an increasing need to better understand the role of natural regeneration of the
herbaceous layer of forests, in addition to regeneration of tree species (Roberts 2004). Two types
of colonizing understory plant species are invaders, which utilize wind as a vector for seed
dispersal, and evaders, which rely on existing seed banks in a disturbed setting (Nguyen-Xuan et
a/. 2000; MacDonald eta/. 2012). Invader plant species, different from invasive plant species,

utilize specific conditions (e.g. disturbance) to propagate in a site, and can spread quickly
(Lieffers and MacDonald 1993). Adding to this complexity is the dominance of some plant
species in areas of low diversity, compared to that of communities with high species diversity
(Grubb 1977). An area of disturbance in a single patch basis may also impact the likelihood of
germination from existing seed banks in boreal forest soils. Greene et a!. ( 1999) postulate that
existing soil seed banks in boreal forests may be inadequate to be a significant source of

69

germinants due to low seed productivity and poor germination rates of seeds in intact forest
floors.

Information about the regeneration of plant species in the Peace region ofn01theastem B.C. is
fragmentary. The topographic and climatic challenges to plant community regeneration at high
elevations, and substrate disturbances that compromise or remove soil horizons and availability
of nutrients are poorly understood. To improve boreal forest ecosystem responses to industrial
activities, it is important to understand how quickly seed banks respond to open forest canopies,
increased soil temperatures, more variable soil moisture, and nutrient availability.

The objective of this study was to determine plant species diversity on a reclaimed natural gas
pipeline right-of-way in northeastern B.C. The research was conducted to address the issue of
plant species richness and abundance observed on a reclaimed pipeline right-of-way in a boreal
forest ecosystem altered by industrial activities. This would fill a knowledge gap regarding plant
community recovery in the Boreal White and Black Spruce wet cool biogeoclimatic subzone
(DeLong eta!. 1991) and Engelmann Spruce - Subalpine Fir moist very cold biogeoclimatic
subzone (Coupe eta!. 1991) in northeastern B.C.

5.2 Materials and Methods

5.2.1 Study Site and Experimental Design
The study sites were located in the northeastern region of B.C., east of the Rocky Mountain
range, and about 40km west of the Alberta border. The site was established in 2007 within the
operations area of Shell Canada (See Chapter 3 for detailed site information). In this study,
control referred to unplanted plots within the study blocks, and treatments referred to the plots
planted with lodgepole pine or sluubby cinquefoil.

70

An unplanted control strip was established by Shell Canada, and unplanted control plots within

the control strips were created by the UNBC research team. Each block had three strips, and
three control plots of 1 m x 1 m were randomly assigned along each strip. Each strip was labeled
as 1, 2 or 3 within each block, numbers increasing from a north-south orientation, each plot was
labeled A, B, C from a left to right orientation. Limitations exist for the small plot size (Brwnmer

eta/. 1994), but still provide useful inventory measures for natural regeneration of early
successional plant species, as increasing plot size can be inconsistent in reducing variance
between grass species, and otherwise may distort diversity values (Brummer et a/. 1994; Zdenka
and Milan 2006).
5.2.2 Sampling and Data Collection

In July and August 20 12 and July 2013, all plant species that appeared within individual plot
boundaries were documented. Square (1m x 1 m for controls, and 2m x 2m for pine and
cinquefoil plots) boundary frames were used for determining counts, and individuals were
excluded when more than 50% of the plant diameter at ground level was outside the plot frame
(Figure 16). For this study, n was the count of individuals observed within the plots. The
numbers of each plant species observed within each plot were counted, which addressed the
species richness present inside the blocks. The numbers of individuals for each species were also
recorded, which accounted for species abundance.

71

Figure 16. Data collection for species diversity, showing square for inclusion/exclusion of plants.

Within the treatments, species were grouped into plant types, which included trees, shrubs, herbs
and graminoids. A separate "other" group was created for mosses, lichens. and species where the
writing was illegible or the species was not identifiable. In this study, two diversity calculations
were performed, one for natural regeneration only, and one which included planted lodgepole
pine and shrubby cinquefoil. In the Results and Di scussion, the natural regeneration only was
used to illustrate diversity (see Appendix 3 for species richness, abundance and diversity values
with planted species included).

The Shannon Diversity Index (fr) was used to determine species diversity within research plots.
This index combines the diversity and abundance of species within the plot area. The equation
used was:
n

H' = - I
i=l

72

pilnpi

where H' was the Shannon Index (Spellerberg and Fedor, 2003), n was number of species, and pi
was the percentage cover of the ith species. The Shannon Diversity Index expresses species
diversity as a unitless number; lower numbers indicate low levels of diversity, and higher
numbers reflect higher species diversity. Values for species diversity can indicate where natural
regeneration is a plausible reclamation strategy, and where more intensive reclamation strategies
are critical for establishing a diverse plant community.

5.2.3 Data Analysis
The independent variables, recorded in percentages, included soil moisture, slope, total nitrogen,
carbon and sulphur, and available phosphorus, plus pH, bulk density, elevation, and presence of
an organic horizon (See chapter 4 for detailed results of soil properties). Species richness was an
independent variable where species abundance was the outcome variable, and species abundance
was used as an independent variable where species richness was the outcome variable. This was
done to understand the potential for abundance of a species to affect the number of species
(species richness) found within the plots, and if the number of species has an effect on the
abundance of a particular plant species.
A Shapiro-Wilk test for normality was performed to validate the species diversity data for
normal distribution. and the a was set at 0.05. An ANOVA was performed to determine if
species diversity was significantly different between zones and blocks. Where significant
differences were shown , a Tukey's test was conducted to determine where significant differences
were located. Where the differences between means were significant, a chart was created with
mean and standard error, and a letter value was applied according to the Tukey group in STATA.
The fi rst mean was given the Jetter "a''. and where differences were discovered in the analysis, a

73

letter "b" was applied. Variables with the same letter (" a", or "ab") were not considered
statistically significant at a= 0.05.
A step-wise regression was initially proposed to analyse the data, however, many collinearity
problems emerged in the analysis results, so a hierarchical regression was used to determine the
variables that significantly affected diversity values. Hierarchical regression (multi-level
modeling) is organised at multiple levels, a three level model was used in this study. In the
analyses, level three referred to the biogeoclimatic zone, level two was related to block, and level
one included fixed classifications (nutrients, bulk density, slope etc.). A primary strength of this
type of analysis is that the three level structure considers within and cross-level interactions
(Osborne 1999; Chi and Voss 2005; Tabachnick and Fidell2007) such as those considered in
this study. The hierarchical regression model was:

Yijk =

11 + lli.. + /lij. + Cijk

where Yijk was the dependent variable, )..l was the grand mean, /li.. was the mean of level 2, /lij.
was the mean of level 3, and Eijk was the error term. From this model, the standard deviation
that accounted for zone, block, and residual standard deviation were included in the tables.

Statistical analysis was performed using STATA® 13.1 (StataCorp LP, College Station, Texas,
USA). Species diversity was the dependent variable considered for analysis, and independent
variables included soil properties, topography (blocks were assigned according so aspect),
treatment, and zone. A 95% confidence level was used for the models. Regression reporting
included the coefficient, standard en-or, random effects, and p value, and results were considered
significant when a ~ 0.05.

74

5.4 Results
The species diversity values met the assumption of normality using the Shapiro Wilk test (a= <
0.05, p = 0.2 12); an ANOVA for species diversity considered differences in mean H' values
between treatment, block, and zone. Significant differences were shown in species diversity
between treatment (F2 , 149 = 8.33, p = 0.000) and block (F3•2o = 8.67, p = 0.000) but not between
zones (F 1,75 = 1.85, p = 0. 178). A Tukey test was conducted to find where the differences were
located, and for treatments, the significant differences were observed between control and pine

(p = 0.001), but not between cinquefoil and control (p = 0.249) or between pine and cinquefoil (p

= 0.22 1) (Figure 17). By block, the Tukey test returned significant differences between wetland
and south facing blocks (p = 0.020), and wetland and crest position blocks (p = 0.001) (Figure
18).

1.8

ell

b

1.6

:::1

... 1.4
(II

ab
a

,....

1.2
:X:
'-'

.q

..

I

"'~ 0.8

:a

"'
0.6
ell
"2 0.4

c.
en 0.2
0
Control

Pine

Cinquefoil

Treatment

Figure 17. Mean with standard error of species diversity (H) value by treatment. Control n = 72, pine n = 55,
cinquefoil n = 23. Letters indicate Tukey results, and means sharing a letter were not significantly different at the a
= 0.05level.

75

2

b

1.8
~ 1.6

0:
;> 1.4
,.._

fl:: 1.2
.._,
0

·;n

...
<:1

;>

:a 0.8
"' 0.6
-~
~

~ 0.4

0.2
0
South-facing (I)

Crest (2)

North-facing (3)

Wetland (4)

Aspect (block)
Figure 18. Mean with standard error of species diversity (H) value by aspect (block). Control n = 72, pine n = 55,
cinquefoil n = 23. Numbers in parentheses represent block designation. Letters indicate Tukey results, and means
sharing a letter were not significantly different at the a = 0.05 level.

Observed plant types were variable between control plots and treatment plots. Tree observations
were highest in pine plots, and lowest in cinquefoil plots (see Appendix 3 for numbers by plant
type). Shrub observation numbers were hjghest in cinquefoil plots. Pine plots had higher
numbers of herbs, followed by cinquefoil plots and control plots. For graminoid (grass) species,
observations were highest in cinquefoil plots in the BWBS 2, 3, and 4, and ESSF 3 blocks.

Species diversity varied between treatments, but was more consistent in pine plots than for
cinquefoil plots (Figure 19, Table 12, Table 13). Natural regeneration values between treatments
were variable in the BWBS zone; in the BWBS 1 and 3 blocks, diversity was highest in pine
plots, while in BWBS 2 and 4 blocks, diversity was highest in cinquefoil plots. In the ESSF
zone, species diversity was highest in pine plots in ESSF I, 2, and 4 blocks, and highest in

76

cinquefoil plots in the ESSF 3 block. Species diversity throughout the study site was consistently
lowest in control plots in each block.

In upland BWBS and ESSF blocks, fireweed (Chamerion (Epilobium) angustifolium) was
recorded in 106 of 120 plots. Occurrences in plots upland ESSF blocks was less (n = 50) than for
BWBS (n = 56) blocks. At lowland blocks, this species occurred in two plots in the BWBS 4
block, and one plot in the ESSF 4 block. T here were very few observations of naturally
regenerated lodgepole pine seedlings in any of the upland blocks, and no observations of
lodgepole pine in either of the wetland blocks. There were no observations of natural
regeneration of shrubby cinquefoil in any block.

5.4.1 Species Diversity
Table 12. Mean and standard error (in parentheses) of naturaJly regenerated species diversity, abundance, and
Shannon Diversity Index (If') value of upland blocks. For each upland block, n = 9 for control plots, n = 8 for pine
plots, and n = 3 for cinquefoil plots.
Species Richness

Species Abundance

H' value (Diversity)

Block

Treatment

BWBS l

Control

6.67 (1.66)

53 .22 (1 5.06)

1.25 (0.33)

Pine

9.38 (2.26)

103.50 (23.14)

1.48 (0.22)

Cinquefoil

7.67 (2.08)

82.00 (35.03)

1.41 (0.17)

BWBS2

BWBS3

ESSF I

Control

5.33 (1.32)

34.22 (13.98)

1.28 (0.25)

Pine

6.75 (0.71)

74.86 (32.59)

1.35 (0.18)

Cinquefoil

7.00 (1.00)

55.67 ( 12.34)

1.45 (0.06)

Control
Pine
Cinquefoil

6.89 (3.14)
11.75 (3.85)
7.33 (1.53)

45.44 (18.66)
102.75 (31.77)

1.38 (0.41)
1.86 (0.43)

87.00 (40.58)

1.48 (0.22)

Control

4.22 (1.79)

24.78 ( 19.66)

1.06 (0.35)

Pine

7.63 (2.13)
4.67 (2.08)

74.63 (26.61)

!.56 (0.29)

27.00 (19.52)

1.08 (0.45)

2.44 (1.81)
7.13(1.64)

10.44 (14.83

0.67 (0.56)

72.25 (40.87)

1.52 (0.35)

Cinquefoil
ESSF2

Control
Pine

ESSF3

Cinquefoil

2.33 (2.52)

5.67 (5.51)

0.70 (0.74)

Control

4.44 (1.81)

41.11 (19.63)

1.11 (0.32)

Pine

7.38 (2.50)

81.13 (32.47)

1.36 (0.40)

Cinquefoil

8.67 (4.73)

111.33 (15.70)

1.53 (0.27)

77

Table 13 . Mean and standard error (in parentheses) of naturally regenerated species di versity, abundance and
Shannon Diversity Index (H') values of wetland blocks. In BWBS 4, control n = 9 pine n = 3*, cinquefoil n = 2**;
in ESSF 4, control n = 9, pine n = 4, cinquefoil n = 3.
Block

Treatment

Species Richness

Species Abundance

H' value (Diversity)

BWBS4

Control

7.11 (1.27)

63.89 (14.80)

1.42 (0.18)

Pine

6.67 {1.53)

68.67 {1 7.62)

1.42 (0.03)

Cinquefoil

9.00(1.4 1)

127.00 (9.90)

1.72 (0.11)

Control

9.44 (3.88)

74 .11 (32.18)

1.55 (0.60)

Pine

14.25 (2.63)

137.75 (52.50)

2.17 (0.21)

Cinquefoil
11 .67 (2.08)
81.00 (26.51)
* One pine plot disregarded due to ongoing plot disturbance by human activities.
** Two plots planted with cinquefoil in BWBS 4.

1.94 (0.30)

ESSF4

3.00

2.50

,-..

cu

=
...

2.00

-;

:t
........ 1.50

~

.q
"'
...""'cu

i:5
"'cu
•<j

r±

d

d

Dcontrol
• pine

1.00

cinquefoil

cu

c.
rn 0.50

0.00

-0.50

...... ' ...... ' - ' BWBS 1 BWBS2 BWBS3 BWBS4 ESSF l
'-

'-

ESSF2

'-

ESSF 3

'-

,_

ESSF4

Block Designation

Figure 19. Mean and standard error (error bars) of natural regeneration Shannon Diversity Index (H') values for
control, pine and cinquefoil plots, all blocks. Plot numbers for each upland block: control n = 9, pine n = 8,
cinquefoil n = 3. For wetland blocks, BWBS 4, control n = 9, pine n = 3*, cinquefoil n = 2**; ESSF 4, control n = 9,
pine n = 4 , cinquefoil n = 3.
* One pine plot disregarded due to ongoing disturbance by human activities
** Two plots planted to cinquefoil in BWBS 4.

78

ANOVAs were run for species diversity to determine whether there were significant clifferences
in control, pine, and cinquefoil plots, based on the H' values calculated from natural
regeneration. The factor variables were significant (p < 0.05) for the controls by treatment (F 2, 72

= 10.87, p = 0.000), and by block (F3,9 = 8.83, p = 0.000) but not by zone (F1,72 = 1.85,p =
0.178).
Table 14. Hierarchical regression for species diversity in combined control, pine and cinquefoil plots, all blocks.
Variable
p
pSE
p (< 0.05)
Moisture
O.Ql
0.01
0.200
0.59
0.023*
N
1.35
0.02
-0.04
c
0.017*
0.64
0.852
0.12
p
O.Ql
0.00
0.008*
-0.41
0.61
0.495
K
0.00
CEC
0.01
0.981
-0.06
pH
0.05
0.276
0.35
Bulk Density
0.13
0.007*
0.00
Elevation
0.00
0.139
Soil temp.
0.995
0.17
0.00
-0.07
LFH
0.37
0.846
0.01
Slope
0.00
0.000*
0.575
Clay
0.01
0.01
0.03
0.11
Treatment
0.001*

s

Random
effects:
Zone (SD)
9.45E-13
Block (SD)
9.11E-13
SD (residual)
0.2264471
* Significant at < 0.05
2

2

The hierarchical regression (Wald chi 149.97, Prob > chi = 0.000) (Table 14) for all treatments,
found that species diversity in all blocks was significantly affected by total N , total C, available
P, soil bulk density, slope, and treatment. As the clay percentage was not considered significant
in the model, a separate regression was perfo1med for each treatment, and excluded clay as a
variable (Table 15).

79

Table 15. Hierarchical regression for species diversity in separate control, pine and cinquefoil plots, all blocks.
Control
Variable
Moisture
N

c

s

p
K
CEC
pH
Bulk Density
Elevation
Soil tem p.
LFH
Slope

Pine

~

~SE

E{< 0.052

0.00

0.00
0.03
0.00
0.04
0.00
0.04
0.00
0.01
0.02
0.00
0.01
0.19
0.00

0.087
0.374
0.186
0.710
0.216
0.922
0.994
0.025*
0.000*
0.000*
0.000*
0.004*
0.000*

O.Q2

0.00
-0.02
0.00
0.00
0.00
0.02
0.18
0.00
0.16
0.56
0.02

Random effects:
Zone (SO)
2.24E-13
Block (SO)
1.90E-O I
SO {residual)
0.0205574
• Significant at < 0.05

~

~ SE

E(< 0.05)

~

0.00
-0.2 1
0.01
-0.41
0.00
-0.04
0.00
-0.04
-0.3 1
0.00
0.40
0.40
0.00

0.00
0.03
0.00
0.05
0.00
0.06
0.00
0.01
0.02
0.00
0.02
0.34
0.00

0.405
0.000*
0.000*
0.000*
0.739
0.503
0.000*
0.000*
0.000*
0.000*
0.000*
0.256
0.387

0.01
-1.69
0.06
2.19
0.00
0.24
0.00
0.10
0.40
0.00
0.00
0.04
0.20

9.88E- l2
3.34E-O I
0.580154

3.40E-1 3
1.59E-O I
0.0445749

80

Cinquefoil
E {< 0.05)
~ SE
0.000*
0
0.23
0.000*
0.01
0.000*
0.29
0.000*
0.00
0.769
0.14
0.080
0.00
0.881
0.03
0.001 *
0.04
0.000*
0.00
0.000*
0.04
0.952
0.19
0.834
0.00
0.000*

5.5 Discussion
Species diversity observations showed that plant species diversity varied by slope aspect of each
block. Wetland blocks had high species diversity, while south-facing and crest blocks were the
least diverse by plant species noted. Treatment was also related to species diversity in many of
the research blocks; control plots were generally the least diverse, and pine plots often had the
highest diversity values within each block.
5.5.1 Aspect
The arrangement of blocks by aspect allowed for distinctions to be made about species diversity
relative to aspect in this study. South-facing and crest blocks had comparably low diversity, and
were statistically similar to each other. Higher values of diversity were observed in north-facing
blocks and wetland blocks in both biogeoclimatic zones.

5.5.1.1 South-facing Blocks
The south-facing blocks had low species diversity (Figure 20). Diversity was lowest in control
plots and highest in pine plots in both biogeoclimatic zones. Both BWBS and ESSF blocks were
adjacent to mature pine stands, however the BWBS I block was adjacent to a frequently used
access road for pipeline maintenance, while the ESSF I block was at a high elevation, and
subjected to wind exposure due to the linear aligrunent of the right-of-way clearing. Some
research bas found that wind exposure in mountainous environments can adversely affect plant
establishment (Litaor eta!. 2008), which was more noticeable at the ESSF I block in this study.

8I

Figure 20. Images of south-facing blocks (top: BWBS I, bonom : ESSF I) showing natura] regeneration recovery.

5.5.1.2 Crest Positio11 Blocks
The BWBS and ESSF 2 blocks both exhibited low levels of plant species diversity (Figure 21).
This find ing is consistent with other research. which has asserted the crest positions have shallow
topsoi l and low moisture values, which can be limiting facto rs to plant establishment (Zinko et

a/. 2005; Pareli ussen eta/. 2006). Soil moisture however, was not a significant contributor to

82

species diversity in this study although values were lowest at crest blocks in both biogeoclimatic
zones (see Chapter 4 ). ln the BWBS 2 block, highest mean diversity was observed in the
cinquefoil plots, while pine plots had the highest diversity values in the ESSF 2 block. Both
blocks were adjacent to a mature lodgepole pine stand, although the BWBS 2 block was part of a
wider right-of-way, as a winter road was present on the west side of the block. The ESSF 2 block
was at high elevation on a conspicuous hill which was also exposed to prevalent winds.

Figure 21. Images of crest position blocks (top: BWBS 2, bottom: ESSF 2) showing natural regeneration recovery.

83

5.5.1.3 North-facing Blocks
Each north facing block in this study was unique. The BWBS 3 block was adjacent to a mature
mixedwood stand, and nutrient, temperature and moisture levels were influenced by leaf litter
and the density and alignment of CWD application. The ESSF 3 block was adjacent to a pure
conifer stand, and arrangement of CWD was lower in volume, and aligned more randomly than
in the BWBS 3 block (Figure 3, Figure 22, Figure 23). Species diversity was high for all
treatments in the BWBS 3 block compared to BWBS 1 and 2 blocks. Species diversity was low

in the pine plots relative to ESSF 1 and 2 blocks in the ESSF zone, but higher in control and
cinquefoil plots compared to other ESSF upland blocks.

Figure 22. lmage of north-facing BWBS block showing natural regeneration recovery.

Site soil richness is an indicator of diversity potential (Widenfalk and Weslien 2009), and the
BWBS 3 block soil property observations showed greater nitrogen, carbon, sulphur and
potassium values than the other upland blocks in the BWBS zone (refer to soil properties results
in Chapter 4). The mean species diversity in this block was highest for all treatments, however
there was also greater variability of diversity observed. The higher species diversity fo r uplands

84

observed in this study is supported by other research (De Bello et a/. 2006).

Figure 23. Image of north-facing ESSF block showing narural regeneration recovery.

5.5.1.4 Wetla11ds

The wetland blocks in this study showed high species diversity values (Figure 24). The BWBS 4
block was adjacent to a black spruce stand, and had extensive colonization by the grarninoid
species bluejoint (Calamagrostis canadensis). This species was recorded in all control,
cinquefoil and two of three pine plots. The height of the grass also provided a competitive
advantage against planted pine and cinquefoil seedlings by the end of the 20 13 growing season.
Th is grass species has been noted as a common invader of disturbed sites in northeastern B.C.
(Macey and Winder 200 I; Krzic eta/. 2003), generally as a result of increased light availability
(Maundrell and Hawkins 2004).

85

Figure 24. Images of wetland blocks (top: BWBS 4, bon om: ESSF 4) showing natural regeneration recovery.

Species diversity and abundance varied by treatment in ESSF 4. This block had a relatively high
diversity of wetland species. The block was at the intersection of two resource roads, and other
research has found negative correlations between human activities and species richness
(Houlahan et a/. 2006). Bluejoint appeared in many of the plots within this block, but there were
also willow (Salix spp.) species, various wetland sedges (Carex spp.), and tamarack (Larix

86

laricina) was regenerati ng naturally (there were plots planted with tamarack in this block), and
there were mature individuals off the pipeline right-of-way.

N itrogen levels between treatments and controls were not significantly different, although the
regression models highlighted that total nitrogen was negatively correlated with species diversity
in the planted plots, but positively correlated for the controls. Net N accumulation has been
asserted as a driver for increased species composition over time (Bobbink et al. 201 0), and this
study noted greater H' values in blocks (BWBS 4, ESSF 4) where total N was hi gh.

5.5.2 Treatment
Species diversity varied by treatment in the study blocks. There was a significant difference
observed between control and pine plots. but not between pine and cinquefoil or control and
cinquefoil. Low species diversity was observed in control plots, while natural regeneration was
variable between pine and cinquefoil plots.

5.5.2.1 Colltrol Plots
The control plots consistently had lower species diversity than pine or cinquefoil plots, likely due
to smaller plot area (Brummer et al. 1994; Zdenka and Milan 2006), which was a fl aw in the
experi mental design. There were plots in the ESSF 2 block where no natural regeneration was
observed. and in the BWBS 4 block, the species di versity value in control plots was the same as
in the pine plots. The control plots however, had lower diversity in all study blocks than either
the pine or cinquefoil treatment, and the results of this study are consistent with other work that
examined the influence of soil disturbance correlated with lower species diversity (Peltzer et al.
2000).

87

Soil properties including pH, bulk density and soil temperature, presence of OM, elevation, and
slope influenced species diversity in control plots. Elevation was negatively correlated with
species diversity, and diversity values were lowest at the ESSF 2 block (elevation 1369 m.a.s.l).
Soil pH was low in ESSF upland blocks, which could account for the association between higher
pH and higher diversity values. Slope was positively associated with diversity, but this may have
been a confounding effect, as crest blocks and wetland blocks were on level ground, and the
associated diversity was low at crest blocks, and high in wetland blocks.

5. 5. 2.2 Pine Plots
Pine plots had the highest species diversity in five of the eight research blocks. This was
observed in both the BWBS and ESSF 1 blocks, and less consistently for the other slope
positions. The diversity values were higher in three ESSF blocks and two BWBS blocks.
Lowland species diversity in the ESSF 4 block was greatest in the lodgepole pine plots, which
showed the greatest diversity by number of species, species abundance, and associated H' value.
Depending on site conditions, lodgepole pine is not always a strong competitor and the young
stand age did not demonstrate that it was outcompeting other species for resources such as light.
The negative association between total N and species diversity in pine plots could be related to
the low diversity value in the BWBS 4 block, where nitrogen levels were high. This block had
extensive bluejoint abundance (Figure 25), and the prevalence ofthis species adversely
influenced species richness in this block. Pine plots in upland blocks were given a ferti lizer
amendment (N:P:K 25:0:0) at planting. TheN levels in pine plots were not higher than N values
in control and cinquefoil plots when soil san1ples were taken in 2012, but the initial input ofN
fertilizer could have influenced establishment of naturally regenerated species soon after the

88

2010 planting year. This idea has been documented by research that evaluated the influence ofN
based fertilizer and plant species richness (Gough el a/. 2000).

Figure 25. BWBS wetland block showing prevalence ofbluejoint (C. canadensis).

5. 5.2.3 Cinquefoil Plots
Species diversity was highest in cinquefoi l plots in three of the eight research blocks. There was
very little diversity however, in the ESSF 2 block in c inquefoil plots (Figure 26). The
calculations of greater mean diversity were made for the BWBS 2 and BWBS 4 blocks, and the
ESSF 3 block. There is some evidence that cinquefoil can act as a species richness facilitator in
some alpine communities (Xu el al. 201 0), although it was not consistent for slope position in
this study. It is possible that the density of planted cinquefoil seedlings adversely affected
species diversity and associated H' value, as this species can form a dominant cover in suitable
conditions (Elkington and Woodell 1963).

89

Figure 26. Cinquefoil plot at ESSF crest block, demonstrating low species diversity observations.

Results of the regression analysis showed that nitrogen, carbon, phosphorus, bulk density, slope
and treatment were significant contributors to naturally regenerated plant species within the
treatments. In upland blocks, pine seedl ings were given a fertilizer addition at planting which
may have temporarily increased total nitrogen levels, but the differences in nitrogen between
treatments was not consistently higher in pine plots in 2012 when soil analyses were performed
(see Chapter 4). Soil carbon values were highest in the BWBS 3 block, and the two wetland
blocks (BWBS 4 and ESSF 4), but carbon values were not consistently associated with any of
the treatments considered in this study. Available phosphorus was variable between the
treatments, but was higher in the ESSF upland blocks than BWBS upland blocks and either of
the wetland blocks. Planting density of shrubby cinquefoil was high, but planting density was
not consistent with low species diversity in cinquefoil plots. Bulk density was a significant
contributor to species diversity, however lowest bulk density values were observed in wetland

90

blocks, where species diversity was higher than in upland blocks. ESSF 4 had the least amount of
area affected by industrial activity for pipeline installation, and had the highest diversity values
by zone and treatment. Slope was correlated with species diversity, but this may have been a
confounding variable, as both crest and wetland blocks did not have a slope percentage, and
wetland blocks had high diversity values, while crest position blocks had low diversity values by
zone. The fmdings of this study are supported by other research that asserts wetlands are highly
productive and dynamic ecosystems (Xiong et al. 2003; 0kland eta/. 2008).
The comparable species diversity in control plots with the treatments in the BWBS 4 block and
the ESSF 2 block in this study suggest that there may be instances were natural regeneration is a
plausible strategy, but the lower values should be cautionary as to the efficacy of natural
regeneration as a reclamation option.

5.4.3 Limitations
This study did not consider ongoing disturbance as a variable, which may have impacted species
diversity by suppressing species that are susceptible to mechanical damage, and for the potential
for introduction of invasive species on vehicles. Soil samples were not analysed for seed bank
content, which could have shown the diversity of viable seeds for future natural regeneration.
Wind was not included in the analysis; it acts as a vector for seed dispersal in some plant species
{Tackenberg et al. 2003), and inhibits successfu l seed establishment when high winds are
combined with poor microsite preparation. The smaller size of control plots may have also
contributed to consistently lower values of diversity compared to pine or cinquefoil plots. This
could have been corrected by use of consistent plot sizes for control and treatment plots.

91

5.5 Conclusion
This study was conducted to determine the effects of industrial activities on the capacity of
upland and wetland sites in mountainous areas of northeastern B.C. to recover naturally after
human-based disturbances. The differences in species diversity between the control, pine, and
cinquefoil treatments showed that planting increased species diversity in the BWBS and ESSF
biogeoclimatic zones in this study. The lower species diversity in control plots than either of the
treatments implies that planting programs can aid in natural regeneration of available seeds, but
high density planting can inhibit species diversity, as was observed in cinquefoil plots. In this
study, higher species diversity was observed in wetland blocks than in upland blocks. The
number of species that were not identified also increased with greater species diversity, and
accurate identification may have altered the numbers by plant type, but not overall diversity. The
greater diversity observed in the ESSF wetland may be related to the greater length of time
between the disturbance and the observation years in this study, although it is unclear if time
would increase the species diversity in the upland blocks or the BWBS wetland block.

Future reclamation projects in the peace region of northeastern B.C. that encompass the BWBS
and ESSF biogeoclimatic zones should include prescriptive planting, as the results of this study
showed that unplanted areas had less natural regeneration than plots planted with lodgepole pine
or shrubby cinquefoil at higher elevation sites in upland research blocks. The slope aspect
variable and surrounding forest types provided valuable knowledge regarding the challenges to
reclamation related to creating a functioning ecosystem along reclaimed pipeline right-of-ways.
Other considerations should be given to traditional use of the land, and input from local First
Nations would provide insight to augmenting planting projects with cultural keystone native
plant species for food or medicinal values.

92

6.0 Growth and Survival of Lodgepole Pine and Shrubby Cinquefoil on a Reclaimed
Natural Gas Pipeline Right-of-Way in Northeastern British Columbia
Abstract
Environmental conditions in boreal forests of western Canada can be challenging to plant
growth. Construction of a disturbance such as a pipeline right-of-way creates aboveground and
substrate disturbance factors that can affect environmental quality. The study objective was to
detennine the growth and survival of lodgepole pine (Pinus contorta var. latifolia) and shrubby
cinquefoil (Dasiphorafruticosa) on a reclaimed natural gas pipeline in northeastern British
Columbia. Lodgepole pine seedlings were measured for aboveground height, stem diameter, and
height diameter ratio (HOR). Shrubby cinquefoil seedlings were measured for total height, stem
count and cover area. There was greater average plant height at BWBS upland and wetland
blocks than at ESSF upland and wetland blocks for lodgepole pine and shrubby cinquefoil
seedlings. The findings suggest that soil physical and chemical properties can influence plant
growth, and reclamation practitioners should consider site conditions when determining species
use in reclamation projects.

93

6.1 Introduction
Forest fragmentation from natural gas infrastructure in n011heastern B.C. is replacing natural
disturbance patterns of boreal forests. Natural disturbance patterns such as fire, wind and insect
outbreaks open forest canopies and facilitate establishment of plant species that produce
serotinous cones. Industrial disturbances in boreal forest ecosystems do not emulate natural
disturbances, and there is a need to understand the differences between natural and industrial
disturbances, and the role of industrial disturbance to plant growth in high elevation boreal
forests.
Industrial disturbances in the south Peace region of northeastern B.C. have increased in recent
years, and have exacerbated forest fragmentation from existing natural disturbance regimes and
forest harvesting. Pipeline construction creates linear forest canopy gaps, removes vegetation,
compromises forest soil horizons, and affects soil temperature and soil moisture regimes (Naeth

eta!. 1987; Shi et al. 2014). Displacement or loss of soil horizons, removal of canopy cover,
edge effect, changes in levels of exposure to minerals and macronutrients, erosion potential, and
alterations in soil moisture and temperature regimes, all alter growing conditions for plants
(Mariani eta/. 2006; Hope 2007).
Although the impacts to vegetation from forestry and vegetation management are well
documented, plant growth after pipeline installations in northeastern B.C. is less well understood.

In order to comprehend plant growth after linear forest harvest and soil horizon disturbance, it is
important to determine how plants respond to altered forest soils.
The primary objective of this study was to determine the effects of industrial disturbance on
plant growth and survival of two selected plant species, lodgepole pine (Pinus contorta var.

94

latifolia), and shrubby cinquefoil (Dasiphorafruticosa) along a reclaimed natural gas pipeline
right-of-way in the Boreal White and Black Spruce zone (wet cool subzone) and the Engelmann
Spruce- Subalpine Fir zone (moist very cold subzone) in northeastern B.C.
6.2 Materials and Methods
6.2.1 Study Site a nd Experimen tal Design
The Ojay research site was situated in a mature managed lodgepole pine stand. Lodgepole pine
dominated the tree canopy in most upland blocks, although one block was adjacent to a
mixedwood stand. Identified canopy species off pipeline at upland blocks included lodgepole
pine (Pinus contorta) at all upland blocks, and at one block in the BWBS zone, trembling aspen

(Populus tremuloides), and balsam poplar (Populus balsamifera) were also observed. Off
pipeline tree species noted at wetland blocks included black spruce (Picea mariana), and
tamarack (Larix laricina ).
The Ojay pipeline was constructed in 2008 in northeastern B.C. In 20 10, eight blocks were
selected by representatives of Shell Canada fo r experimental planting at upland and wetland
sections of the pipeline right-of-way (see Chapter 3 for further site details). Within each block,
there were plots planted with lodgepole pine (eight in each upland block, four in each wetland
block), and shrubby cinquefoil (three in each block except BWBS 4, where two cinquefoil plots
were established and planted.
6.2.2 Sampling and Data Collection

In June 2012, pine and cinquefoi l seedlings were identified and tagged within each plot.
Exclusion and inclusion criteria involved confumation of plot boundaries with a 2 m x 2 m

95

square, and seedlings with fifty percent or more of the main stem outside the square were
excluded from future measurement.
Table 16. Biogeoclimatic zone, block designation, and numbers of pine and cinquefoil seedlings selected for
monitoring in 2012 and 2013.
Cinquefoil

Pine
Block

Designation*

BWBS

I

BWBS

2
3
4

BWBS
BWBS
ESSF

Seedlings measured

2012
96
94
80
36t
67

ESSF

2

72

ESSF

3
4

68
43
556

ESSF

2013
96
94
80
36t
67
67
66
43
549

Seedlings measured

2012
15
15
14
9t
15
14
13
15
I I0

n=
BWBS- Black White Boreal Spruce biogeoclimatic zone
ESSF- Engelmann Spruce Subalpine Fir biogeoclimatic zone
*Block description
1 -South-facing block
2- Crest block
3 -North-facing block with CWD amendment
4- Wetland block
t-One pine plot disregarded due to ongoing disturbance
t- Two cinquefoil plots were established

2013
15
15
14
9t
15
14
13
15
I 10

Lodgepole pine and shrubby cinquefoil seedlings were monitored for survival and growth in
August 2012 and 2013. All living pine seedlings in all blocks were measured, and one quarter of
planted cinquefoil seedlings per plot were selected for measurement (Table 16). Measurement of
pine seedlings was based on guidelines from the BC Ministry of Forests Land and Natural
Resource Operations (BC MFLNRO) for plants measuring less than 3 metres. In samples where
the main stem was dead, but there was evidence of compensatory growth from a lateral stem,
height measurement for the tallest lateral leader was taken. Stem diameter was taken from a point
of the stem 1 em from soil surface, where two diameter measurements were taken. Stem
diameter was measured with calipers, and plant height measured with a carpenter's measuring
tape. Height-Diameter Ratio (HDR) was calculated for lodgepole pine by dividing the tree height

96

(em) by the stem diameter (em) (Opio eta!. 2003). For cinquefoil seedlings, total height, cover
area by two cross-sectional measurements were recorded, and stems for each sample plant were
counted. Any damage to plants caused by biotic or abiotic factors was noted, and any plants that
died or otherwise missing throughout the data collection period were excluded from final
analysis except as a measure of plant survival.
In the second year of data collection, some samples were harvested for biomass measurements.
Guidelines for sampling of tree seedlings and understory herbs followed those used by the
Canadian Forest Service (Catchpole and Wheeler 1992; Tremblay and Larocque 2001; Miao and
Li 2007). Samples were weighed as wet samples, and then oven dried at 70° C for five days, after
which samples were re-weighed, and dry weights were recorded for each sample. Each sample
plant was then cut and weighed separately for aboveground (stems and leaves) and belowground
(roots) measurements.
6.2.3 Data Analysis
Soil physical and chemical properties including temperature, moisture, bulk density, pH, carbon,
nitrogen, sulphur, phosphorous, potassium, cation exchange capacity, particle size, plus slope
and elevation were considered as independent variables in this study (see chapter 4 and
Appendix 1 for comprehensive methods and analysis). Species diversity (species richness and
species abundance; see Chapter 5 for results) was also considered to determine potential effects
of competition to survival and growth of lodgepole pine and shrubby cinquefoil.
Plant growth data were subjected to the Shapiro-Wilk test for normality, as it is considered
statistically more powerful in comparison to some other methods (Kolmogorov-Srnimov,
Lilliefors, and Anderson-Darling tests (Razali and Yap 2011 )). An ANOV A was performed to

97

determine if growth parameters were significantly different between zones and blocks. Where
significant differences were recorded in the ANOVAs, a Tukey test was performed to discern the
likely areas of significant differences. Where the Tukey test returned significant differences, a
letter was assigned to the group. The first mean was given the letter "a'', and where differences
were observed in the analysis, a letter "b" was applied. Variables with the same letter ("a", or
"ab'") were not considered statistically significant at a = 0.05.
A step-wise regression was initially proposed to analyse the data, however, many collinearity
problems emerged in the analysis results, so a hierarchical regression was used to determine the
variables that significantly affected diversity values. Hierarchical regression (multi-level
modeling) is organised at multiple levels; a three level model was used in this study. In the
analyses, level three referred to the biogeoclimatic zone, level two was related to block, and level
one included fixed classifications (nutrients, bulk density, slope etc.). A primary strength of this
type of analysis is that the three level structure considers within and cross-level interactions
(Osborne 1999; Chi and Voss 2005; Tabachnick and Fidell 2007) such as those considered in
this study. The hierarchical regression model was:

where Yijk was the dependent variable, ~L was the grand mean, fli.. was the mean of level 2, /lij.
was the mean of level 3, and Ei j k was the error term. This regression analysis allowed us to
determine which independent variables were most important in determining the best location for
a give plant species.
Statistical analysis was performed using STATA® 13.1 (StataCorp LP, College Station, Texas,
USA). Dependent variables considered for analysis included growth parameter measurements
98

and plant survival, and independent variables included soil physical and chemical properties,
topography, block, and biogeoclimatic zone. A 95% confidence level was used for the models.
Regression reporting included the coefficient, standard deviation, random effects parameters, and
p value; results were considered significant when a < 0.05.

6.3 Results
Lodgepole pine seedling growth was complex, as plants were taller in north-facing block, while
total biomass was highest in crest block in both the ESSF and BWBS biogeoclimatic zones. Pine
mortality was consistently higher in the ESSF zone than the BWBS zone. Shrubby cinquefoi l
seedlings were also tallest in BWBS and ESSF 3 blocks, yet total biomass was greatest in BWBS
and ESSF I blocks. Growth and biomass of lodgepole pine and shrubby cinquefoil was low in
wetland blocks.
6.3.1 Plant Growth
Lodgepole pine seedlings were measured for total height, stem diameter, HDR; and shrubby
cinquefoil seedlings were measured for total height, and cover area. In August 2013,
representative individuals from each planted plot were destructively sampled, and both species
were weighed for aboveground, belowground, and total biomass.

6.3.1.1 Lodgepole Pi11e
Plant growth and survival data were subjected to the Shapiro-Wilk test for nonnality. The height
data for pine met the criteria for normality at a= 0.05 (p = 0.493). Pine stem diameter was also
normal at a = 0.05 (p = 0.086). The ANOV A for plant height showed significant differences in
pine height means by block (F3 , 95 = 3.58, p = 0.020) and by zone (F1, 330 = 9.76, p = 0.003). The
Tukey test for pine height observed significant differences between I and 3 blocks (p = 0.024)
(Figure 27).

99

400

b

350
,.... 300

s

-

~ 250

~ 200
~

-=c ISO
~

s: 100
50
0
South-facing (I)

Crest (2)

North-facing (3)

Wetland (4)

Aspect (Block)

Figure 27. Mean and standard error of pine seedling height by block. Numbers in parentheses represent block
designation. Letters indicate Tukey results, and means sharing a letter were not significantly different at the a = 0.05
level.

The ANOV A results for stem diameter of pine seedlings showed significant differences between
means by block (F3, 95 = 4.86, p = 0.005), but not by zone (F 1, 33o = 0. 16, p = 0.695) (Figure 28).
The results of the Tukey test observed significant differences between south-facing and crest
blocks (p = 0.009), and between crest and wetland blocks (p = 0.014).
9
b

8
,.... 7

s

,§_ 6
lo

~
~

5

...."0~ 4
8c:.l 3

v; 2
0
South-facing (I)

Crest (2)

North-facing (3)

Wetland (4)

Aspect (Block)

Figure 28. Mean stem diameter with standard error by aspect (block). Numbers in parentheses represent block
designation. Letters indicate Tukey results, and means sharing a letter were not significantly different at the a = 0.05
level.

100

For lodgepole pine, average change in seedling height growth between 20 12 and 2013 was
greatest at ESSF and BWBS 2 blocks (Figure 29, Table 17, Table 18). Height accumulations
were lowest in BWBS and ESSF 4 blocks (57.78 mm average for BWBS 4; 40.09 mm average
for ESSF 4). AN OVA results for pine height between biogeoclimatic zones showed that
differences in plant height between zones (F,, 33o = 54.97, p = 0.000) and blocks (F3, 9s = 14.44, p

= 0.000) were significant. For stem diameter, the difference was not significant between zones
(FI,330 = 0.67,p = 0.412) but was significant between blocks (F3, 95 = 27.6 1,p = 0.000).

500
450
400
,..... 350

e

-

S 3QO

.c
·~ 250

:c

=200
Cll

s:: 150
100

50

0
BWBS I BWBS 2 BWBS 3 BWBS 4 ESSF I ESSF 2 ESSF 3 ESSF 4
Block Designation
Figure 29. Mean plant height with standard error (lodgepole pine) for 2012 and 2013 seasons. BWBS I n = 96,
BWBS 2 n = 94, BWBS 3 n = 80, BWBS 4 n = 37; ESSF I n = 62. ESSF 2 n = 66, ESSF 3 n = 68, ESSF 4 n = 43.
• Numbers effective in 2013, and immediately prior to destructive sampling.

The model for stem diameter (Wald Chi 2 = 35.33, Prob > Chi2 = 0.000) showed that, of the
variables considered, soil bulk density and slope were significant contributors to pine stem
diameter. Bulk density was positively associated with stern diameter, and slope was negatively
associated with stem diameter (Table 20).

101

Table 17. Mean plant height and stem diameter with standard error ((±) reported in parentheses) of upland lodgepole
. fior 2012 an d 2013 , plus
ptne
I mean change b etween measurement years.
Block

2013

Height (mm)

Stem
Diameter
(mm)

Interannual change
Stem
Diameter
Height (mm)
(mm)

4 .62 (0.93)

311.45 (94. 17)

6.13 ( 1.42)

66.8 1 (46.03)

1.5 1 (0.82)

5.04 (1.19)

333.91 (115.63)

7.46 (2.02)

110.86 (55.17)

2.41 (1.29)

93.70 (41.74)

2.09 (0.96)

88.56 (54.64)

1.57 (1.54)

7.82 (3.29)
124.03 (86.16)
ESSF 2
159.66 (113.44) 5.22 (2.05) 261 .99 ( 191.97)
6.42 (2.35)
79.92 (62.78)
ESSF 3
213.01 (130.44) 4.83 (1.94) 284.87 (183.58)
BWBS 1 n = 96, BWBS 2 n = 94, BWBS 3 n = 80; ESSF 1 n = 62, ESSF 2 n = 66, ESSF 3 n = 68.

2.26 (2.03)

20 12

Height (mm)

Stem
diameter
(mm)

BWBSl

244.64 (66.44)

BWBS2

223.05 (91.71)

BWBS3

276.50 (63.70)

4.25 (.079)

370.20 (90.45)

6.34 (1.40)

ESSF I

92.43 (52.35)

3.85 {1.73)

170.75 (97.01)

5.60 (2.25)

1.25 (2.31)

Table 18. Mean plant height stem diameter and interannual change (standard error reported in parentheses) of
lodgepole pine in wetland blocks.
Block

Height (mm)

Stem
Diameter
(mm)

Interannual change
Stem
Diameter
(mm)
Height (mm)

4.61 (0.93)

336.22 (73.71)

5.84 {1.23)

57.78 {31.99)

1.23 (0.69)

ESSF 4
204.72 (46.93) 4.01 (0.58)
BWBS 4 n = 37, ESSF 4 n = 43.

244.81 (56.39)

5.05 (0.96)

40.09 (30.80)

1.04 (0.74)

BWBS 4

2012

2013

Height (mm)

Stem
diameter
(mm)

282.27 (66.22)

Height diameter ratio data were not normally distributed (p = 0.0 11 ) in this study. The ANOVA
showed signi ficant differences by block (F3, 95 = 8.09, p = 0.000) and by zone (F 1, 330 = 30.14, p =
0.000). The Tukey test found significant differences between I and 3 blocks (p = 0.023) and
north-facing and crest blocks (p = 0.020) (Figure 30). The Tukey test returned a significant
differenc.e between zones (p = 0.000). The mix ed effects regression performed for HDR (Wald
2

chi 117.01 , prob > chi 2 = 0.000) (Table 20) showed that soil moisture, elevation, and species
richness were negatively correlated with HDR, and phosphorus, potassium, pH, and species
abundance were positively cotTelated.

102

70
b

ab

North-facing (3)

Wetland (4)

60
0

~ 50
~

...

~ 40

s

=30
Q
.!.

~ 20

:tl

10

0
South-facing (I)

Crest (2)

Aspect (Block)

Figure 30. Mean and standard error of Height-Diameter Ratio by block. Numbers in parentheses represent block
designation. Letters indicate Tukey results, and means sharing a letter were not significantly different at the a= 0.05
level.
Table 19. Height diameter ratio (HDR) for lodgepole pine in 2012 and 2013 plus interannual change; standard error
(±)reported in parentheses. BWBS 1 n = 96, BWBS 2 n = 94, BWBS 3 n = 80, BWBS 4 n = 37; ESSF I n = 62,
ESSF 2 n = 66, ESSF 3 n = 68, ESSF 4 n = 43.
HDR 2012

HDR 2013

Interannual change

BWBS I

53.09 (10.83)

50.79 (9.35)

-2.30

BWBS 2

44.13 (16.14)

44.98 (10.90)

0.86

BWBS 3

65.69 (12.92)

58.53 (9.40)

-7.16

BWBS4

61.12 (13.89)

58.45 (I 1.1 0)

-2.67

ESSF I

25.54 (11.55)

33.41 (10.99)

7.87

ESSF 2

30.45 (15.97)

35.92 (16.41)

5.48

ESSF 3

45.78 (21.29)

46.37 (17.50)

0.58

ESSF4

50.70 (7.52)

48.63 (7.53)

-2.07

103

T able 20. Results of mixed effects regression for lodge12ole Eine total height, stem diameter, and HDR.
Height
Stem Diameter
HDR
Variable
!:! {< 0.05}
!:! {< 0.05}
~ SE
~ SE
~SE
~
~
~
-0.46
-0.02
0.05
0.633
-0.08
0.29
Moisture
3.35
0.890
-27.30
26.66
-628.11
0.042*
-8.46
4.68
0.070
N
309.46
0.17
0.60
0.95
7.59
11.01
0.491
0.08
0.613
c
2.55
5.33
0.632
4.99
30.41
175.86
352.98
0.618
s
p
0.94
0.02
0.0 1
0.136
0.30
0.08
2.43
0.010*
5.92
0.201
31 .30
33 .75
489.26
391.84
0.212
7.57
K
0.12
0.07
0.114
0.17
0.42
0.130
7.35
4.86
CEC
7.41
2.66
0.297
-0.25
0.47
0.597
pH
32.21
30.87
Bulk Density
210.02
89.33
0.019*
3.01
1.35
0.026*
12.82
7.70
-0.02
0.02
0.359
-0.27
0.11
Elevation
-2.26
1.26
0.073
0.1
01
1.82
1.69
0.28
1
16.66
9.61
Soil temp.
-182.97
111.60
-10.17
-214.34
221.82
0.334
-3.58
3.35
0.285
19.11
LFH
-0.06
0.02
0.11
0.12
1.38
0.112
0.004*
Slope
-2.20
Clay
-6.44
0.301
0.08
0.09
0.383
-1.42
0.54
6.23
Random
effects:
Zone (SD)
1.66E-07
Block (SD) 7.45E-08
80.2705
SD {residual}
* Significant at < 0.05

l.47E-12
6.05E-13
1.213096

!:! {< 0.05}
0.783
0.294
0.525
0.870
0.000*
0.354
0.688
0.005*
0.096
0.012*
0.083
0.595
0.378
0.008*

3.20E-09
1.04E-09
6.914726

The Shapiro-Will< test for normality showed biomass of destructively sampled pine seedlings
(aboveground biomass p = 0.000, below ground biomass p = 0.000 and total biomass p = 0.000)
were not normally distributed.

Height to diameter ratio changes were variable within blocks and zones. There was a negative
change in BWBS 1 and 3 blocks, and both the BWBS and ESSF 4 blocks. The BWBS 2 block
and the three upland ESSF blocks showed an increase in HDR between the two measurement
years. An ANOVA test demonstrated that the differences in HDR was significant between
biogeoclimatic zone (F1, 33o= 137.96, p = 0.000) and between blocks (F3, 9s = 40.36, p = 0.000).

In the BWBS upland blocks, greatest pine biomass was observed in the BWBS 2 block, while
biomass in the 1 and 3 blocks was similar, and lowest biomass was found in the BWBS 4 block
(Figure 31, Table 21 , Table 22).

104

Table 21. Mean whole plant oven-dry biomass with standard error (reported in parentheses) of lodgepole pine
seedlings (approximate age = 4 years at time of sampling in 2013) in upland blocks. BWBS l n = 8, BWBS 2 n = 8,
BWBS 3 n = 8; ESSF I n = 8, ESSF 2 n = 8, ESSF 3 n = 8.
Stems (g~

Needles (g)

BWBS 1

4.32 (2.89)

4.72 (3.60)

9.04 (6.45)

2.41 (0.78)

11.45 (7.06)

BWBS2

6.95 (5.53)

8.16 (6.29)

15.11 (6.45)

3.51 (1.87)

18.62 (13.48)

BWBS3
ESSF 1

4.95 (2.26)

4.80 (2.32)

9.75 (4.55)

2.25 (0.88)

12.00 (5.30)

2.20 (1.26)

2.36 {1 .64)

4.56 (2.84)

1.79 (1.15)

6.35 (3.85)

ESSF2

9.72 (9.54)

12.92 {14.86)

22.64 {24.34)

5.21 (4.24)

27.86 (28.52)

ESSF3

5.24 {5.21 ~

5.21 (4.96)

10.45 {10.092

1.91 (1.36)

12.36 {11.352

Block

Total aboveground (g)

Roots (g2

Total Biomass (g)

Table 22. Mean whole plant biomass with standard error (reported in parentheses) of lodgepole pine in wetland
blocks. BWBS 4 n = 3, ESSF 4 n = 4.
Block

Stems (&2

Needles (g)

Total aboveground (g)

Roots (g)

Total Biomass (g)

BWBS 4

4.89 (2.82)

3.28 (3.03)

8.17 (5 .84)

2.73 (1.83)

10.89 (7.59)

ESSF 4

1.74 (0.062

1.21 (0.65)

2.95 (1.20)

1.20 (0.04)

4.16 (1.54)

50.00

40.00

'C:O 30.00
....,

"'"'0:

s 20.00
:.c...

• Aboveground biomass

0

Belowground biomass

c

0:

c. 10.00
0.00
S BWBS BWBS BWBS ESSF I ESSF 2 ESSF 3 ESSF 4
2
3
4

-10.00

Block designation

Figure 31. Mean above and below ground biomass with standard error of oven-dry lodgepole pine seedlings in all
blocks. BWBS 1 n = 8, BWBS 2 n = 8, BWBS 3 n = 8, BWBS 4 n = 3; ESSF I n = 8, ESSF 2 n = 8, ESSF 3 n = 8,
ESSF 4 o = 4.

The ANOVA for aboveground biomass showed that differences were not significant between
zones (F1, 28 = 2.81 , p = 0.094), but were significant between blocks (F3, 8 = 38.57, p = 0.000);
and belowground biomass differences were significant between zones (F1, 28 = 4.55, p = 0.033)
105

and blocks (F3 • 8 = 45.02,p = 0.000). For total biomass, differences were not significant between
zones (F1, 28 = 3.09, p = 0.079) but were significant between blocks (F3• 8 = 39. 74, p = 0.000). In
all BWBS blocks, most of the biomass was attributed to stems and needles. In the ESSF blocks,
samples from the ESSF 2 block had more than double the biomass of the other upland blocks,
and samples from the ESSF 3 block had almost double the biomass of the ESSF 1 block.
Samples from the wetland block had the least biomass in the ESSF zone. Aboveground biomass
in the ESSF upland blocks accounted for most (greater than eighty percent) of the total biomass,
and needle biomass was greater than stem biomass (Table 2 1) in the ESSF 1 and 2 blocks than in
the ESSF 3 block.
6.3.1.2 Shrubby Cillquefoil
Normality was achieved for height of cinquefoil (p = .682). Cinquefoil height was variable for
upland blocks. Height was greatest in north-facing blocks and lowest in crest position blocks in
both zones. ANOV A results showed that the differences in height by zone was not significant
(Fus = O.ll,p = 0.746); however, the differences by block were significant (F3 • 15 = 14.48,p =
0.000). Results of the Tukey test showed significant differences in cinquefoil height between the
wetland and south-facing blocks (p = 0.026), and between wetland and north-facing blocks (p =
0.013), while the means for seedlings in south-facing and north-facing blocks were similar
(Figure 32).

106

450

b

400
,...._

350

8 300
8

'-'

.:::: 250
0.0

] 200
....r::
"' 150

iS:

100

50
0
South-facing ( I)

Crest (2)

North-facing (3)

Wetland (4)

Aspect (Block)

Figure 32. Mean and standard error of cinquefoil height by aspect (block). Numbers in parentheses represent block
designation. Letters indicate Tukey results, and means sharing a letter were not significantly different at the a = 0.05
level.

Height values for each zone were lowest in the wetland blocks (BWBS 4, ESSF 4), and changes

in height were smallest in each wetland block (Figure 33, Table 23, Table 24).

600
500

-=-9 400
r::

...

'-'

..:::::;

.~ 300
Ql

..::

....

; 200

iS:

100
0
BWBS 1 BWBS 2 BWBS 3 BWBS 4 ESSF 1

ESSF 2

ESSF 3

ESSF 4

Block Designation

Figure 33. Mean plant height and standard error for 2012 and 2013 shrubby cinquefoil all blocks. BWBS 1 n = 14,
BWBS 2 n = 15, BWBS 3 n = 14, BWBS 4 n =9; ESSF 1 n = 16, ESSF2 n = 14,ESSF3 n = 13, ESSF 4 n = 15.

107

Cover area data were not normally distributed (p = 0.021) for cinquefoil. ANOVA results
showed significant differences between blocks (F3 , 15 = 4.79,p = 0.013) but not between zones

(F1,5 5 = 0.21, p = 0.651 ). The Tukey test returned significant differences between wetland and
south-facing blocks (p = 0.009) (Figure 34).

600
b
500
ab
::;"" 400

8u

ab

'-'
eo!

~ 300

CIS

...

...0
u 200
~

a

100

0
South-facing (I)

North-facing (3)

Crest (2)

Wetland (4)

Aspect (block)

Figure 34. Mean and standard error of cinquefoil cover area by block. Numbers in parentheses represent block
designation. Letters indicate Tukey results, and means sharing a letter were not significantly different at the a = 0.05
level.

Cover area of cinquefoil differed in each block, highest cover area was noted in the BWBS 1
block, and the ESSF 2 block (Table 23). Differences in cover area were not significant by zone

(F1, 55 = 2.82, p = 0.096), but were significant by block (F3, 1s = 14.52, p = 0.000). Cover area in
wetland blocks was low, and changes in cover area between 2012 and 2013 were greater in the
ESSF 4 block than the BWBS 4 block (Table 24).
The Wald chi 2 for cinquefoil height was 61.11 (prob > chi2 = 0.000), and the Wald chi2 was
68.60 (prob > chi2 = 0.000) for cover area (Table 25). Species abundance, a key component of
108

species diversity, was significant for plant height, while soil properties and topography were
significantly correlated with cover area.
Normality was not achieved for aboveground biomass (p = 0.000), or for total biomass (p =
0.005), however it was achieved for belowground biomass (p = 0.077). Cinquefoil displayed
higher allocation ofbiomass to aboveground stems and leaves in xeric blocks, and higher
biomass allocation to roots in the BWBS 4 block (average BWBS 59%, ESSF 53%) (Table 27
and 28). The differences in aboveground biomass by block were significant (F3, 3 = 19.68, p =
0.000). By zone, average total biomass for the BWBS 4 block was lower (7.58 g) per block than
upland blocks, and differences in aboveground biomass were significant by zone (F,, 22 = 22.89,
p = 0.000). Belowground biomass in upland blocks was lowest in BWBS and ESSF 3 blocks,

and highest in BWBS and ESSF 2 blocks, however the differences were not significant by zone
(F,, 2 2 = 1.09, p = 0.31 0), but were significant by block (F3 , 3 = 3.85, p = 0.027). Despite the

differences in biomass between block, they were not statistically significant (Figure 35).

109

Table 23. Mean plant height and cover area (standard error reported in parentheses) for 20 12 and 2013 with interannual change, shrubby cinquefoil upland
blocks. BWBS In = 14, BWBS2 n = 15,BWBS3n = 14;ESSF In = 16,ESSF2 n = 14,ESSF3 n = 13.

I

20 12

I

Cover area cm2

Interannual change
Height
Cover area
(mm)
(cm 2)

355.00 {119.49)

376.78 ( 185.94)

52.2

56.12

154.73 (102.91)

328.00 (8 1.17)

340.68 (254.5 1)

40

185.95

204.77 ( 135.94)

71.71

11 9.84

Block

Hei ht (mm)

BWBS I

302.80 (98.30)

320.67 ( 124.55)

BWBS2

288.00 (68.86)

20 13

BWBS 3

304.00 (117.65)

84.93 (48.80)

375.71 (137.39)

ESSF I

323.44 (78.15)

114.33 (227.1 1)

391.33 (89 .63)

140.82 (281.48)

67.9

26.49

ESSF 2

176.29 (40.80)

113.48 (90.00)

249.79 (83.78)

388.48 (326.84)

73.5

275

ESSF 3

299.23 ( 141.65)

243.46 (224.05)

416.54 (129.93)

22 1.15 ( 179.43)

117.3 1

-22.3 1

Table 24. Mean plant height and cover area (standard error reported in parentheses) with interannual change shrubby cinquefoil wetland blocks. BWBS 4 n = 9,
ESSF4n = 15.

I

20 12
Hei ht (mm)

Cover area (crn2

BWBS4

20 1.78 (60.99)

84.19 (39.71)

ESSF 4

2 11.00 (59.59)

74.42 (24.57)

Block

I

2013
Cover area (cm2 )

Interannual change
Height
Cover area
(mm
(cm 2

203.33 (47.30)

113.17 (50.19)

1.56

28.97

238.20 (93.76)

126.37 (50. 76)

27.2

51.95

110

Table 25. Hierarchical regression of cinguefoil height and cover area.
Height
Variable
Moisture
N

c
s
p

K
CEC
pH
Bulk Density
Elevation
Soil temp.
LFH
Slope
Clay

~

~ SE

e{< o.o52

-22.55
-4 128.78
128.88
-4399.61
-1.20
874.98
27.82
58.38
516.53
-0.91
-319.99
-39.97
1.22
5.99

19.19
2970.72
73.1 7
1325.05
12.40
709.47
23.59
77.15
218.74
3.87
364.25
944.25
2.60
28.32

0.240
0.165
0.078
0.001 *
0.923
0.217
0.238
0.449
0.018*
0.815
0.380
0.966
0.638
0.832

p (<

~

~ SE

0.052

- 14298.56
-426743.60
3593.57
-1384259.00
-1265.66
305762.70
10356.42
30097.88
149556.30
-1818.96
-215654.50
-332488.20
-3 12.88
3411.29

4120.28
637860.20
15710.58
284508.30
2662.80
152333.60
5064.39
16564.67
46996.95
830.58
78209.91
202745.80
557.29
6080.28

0.001*
0.503
0.819
0.000*
0.635
0.045
0.041 *
0.069
0.001*
0.029*
0.006*
0.101
0.575
0.575

Random
effects:
Zone (SD)
1.33E-07
Block (SD)
2.66£-08
SD {residual} 89.71543
• Significant at < 0.05
5

a

Cover Area

0.0000613
1.18E-05
19263.31

a

4.5

Cii
._.,

4

~ 3.5

=
s

0

3

a

a

North-facing (3)

Wetland (4)

:E

-g 2.5

..

::
0

~

2

>

.§ 1.5
~

=
0.5
0
South-facing (I)

Crest (2)

Aspect (Block)

Figure 35. Mean and standard error ofbelowground (root) biomass by block. Numbers in parentheses represent
block designation. Letters indicate Tukey results, and means sharing a letter were not significantly different at the a
= 0.051evel.

111

The lowest average biomass of cinquefoil seedlings in the ESSF zone upland blocks was the
ESSF 3 block, which had an average biomass of 10.11 g (Table 27). Total mean biomass of
samples from the ESSF 4 block had the lowest average for the zones (Table 27). Total biomass
values were significantly different by zone (F1, 12 = 26.48, p = 0.000) and by block (F3, 3 = 22.62,
p = 0.000).
Table 26. Means and standard error (reported in parentheses) of whole plant oven-dry biomass shrubby cinquefoil in
u2land blocks. BWBS I n = 3, BWBS 2 n = 3, BWBS 3 n = 3; ESSF I n = 3, ESSF 2 n = 3, ESSF 3 n = 3.
Block

Stems{~)

Leaves {g2

Total aboveground {g2

Roots (~2

Total Biomass (g2

BWBSI

5.39 (1.48)

1.80 (0.65)

7.19 (2.13)

3.69 (0.88)

I 0.88 (2.95)

BWBS2

4.14 (3.07)

1.39 (0.91)

5.53 (3.98)

4.16 (1.24)

9.69 (4.69)

BWBS3

1.35 (0.92)

0.27 (0.19)

1.62 (1.07)

1.14 (0.26)

2.76 (1.14)

ESSF I

7.62 (6.82)

2.65 (1.93)

I 0.27 (8.63)

4.55 (2.35)

14.82 (10.90)

ESSF 2

3.48 (I .38)

1.96 (1.18)

5.44 (2.54)

4.67 ( 1.87)

I 0.11 (4.40)

ESSF 3

5.24 (7.202

1.10 (1.66)

6.34 (8.86)

2.25 (2.14)

8.59 (11.00}

Table 27. Means and standard error (reported in parentheses) of whole plant biomass shrubby cinquefoil in wetland
blocks. BWBS 4 n = 2, ESSF 4 n = 3.
Block

Stems (g)

Leaves (g)

Total aboveground (g)

Roots (g)

Total Biomass (g)

BWBS 4

0.81 (0.60)

0.32 (0.30)

1.13 (0.90)

1.28 (0.26)

2.41 (l.l6)

ESSF 4

2.05 (0.51)

0.62 (0.2!2

2.67 (0.702

2.26 (0.52}

4.93 (0.41)

Total biomass ANOV A fo r shrubby cinquefoil showed that there were no significant differences
between blocks (F3. 3 = 2.25, p = 0.11 8) or zones (F1, 12 = 1.43, p = 0.247). Mixed effects
regressions were performed for aboveground, belowground, and total biomass of shrubby
cinquefoil (Table 28). Aboveground biomass regression Wald chi2 was 671.39 (prob > cru2 =
0.000). Results for belowground biomass Wald chi 2 was 626.20 (prob > chi 2 = 0.000). Total
biomass Wald chi2 was 79 1.55 (prob > chi2 = 0.000).

112

20

15

• Aboveground biomass

I

• Belowground biomass

0
WBS 1BWBS 2BWBS 3 BWBS 4 ESSF 1 ESSF 2 ESSF 3 ESSF 4
-5

Block d esignation

Figure 36. Mean above and belowground plant biomass shrubby cinquefoil all blocks. BWBS 1 n = 3, BWBS 2 n =
3, BWBS 3 n = 3, BWBS 4 n = 2; ESSF 1 n = 3, ESSF 2 n = 3, ESSF 3 n = 3, ESSF 4 n = 3.
Table 28. Hierarchical regression for cinguefoil biomass {aboveground, belowground1 and total biomass}.
Aboveground
Belowground
Total
Variable
~ {< 0.05}
~ {< 0.05}
~ SE
~SE
~SE
~
~
~
Moisture
-0.91
0.33
-0.56
0.15
-1.55
0.51
0.006*
0.000*
N
347.77
62.40
0.000*
11.13
22.56
0.622
183.06
78.81
-9.82
-0.37
0.515
-5.41
1.94
1.59
0.000*
c
0.56
-474.44
23.25
0.000*
- 130.11
10.06
0.000*
-583.47
35.15
p
-0.29
0.21
0.172
0.12
0.09
0.222
-0.13
0.33
K
77.07
13.17
21.13
5.39
0.000*
0.000*
122.2
18.82
CEC
-0.45
0.44
0.308
0.28
0.18
0.125
0.62
0.63
pH
14.93
10.70
1.34
0.000*
3.26
0.59
0.000*
2.05
Bulk Density
4.33
11.04
29.02
0.000*
1.66
0.000*
50.56
5.8
Elevation
-0.55
0.13
0.000*
-0.08
0.03
0.005*
-0.46
0.1
Soi l temp.
-60.85
11.48
-11.16
2.77
-62.84
0.000*
0.000*
9.66
27.10
-18.53
7.17
LFH
-156.86
0.000*
0.010*
-138.17
25.05
Slope
0.44
0.15
0.03
0.02
0.192
0.34
0.003*
0.07
Clay
5.03
0.57
0.000*
0.53
0.22
0.014*
4.13
0.75

s

Random
effects:
Zone (SO)
2.33£-08
Block (SO) 3.15£+00
SO (residual2
1.55
• Significant at< 0.05

8.57£-11
8.74£-12
0.6813203

113

1.61£-11
1.74£-10
2.380049

~ {< 0.05)

0.002*
0.020*
0.005*
0.000*
0.687
0.000*
0.325
.000*
.000*
.000*
.000*
.000*
.000*
.000*

6.3.1.3 Plant Mortality
Plant mortality of lodgepole pine varied between zones (Figure 37). Normality of pine mortality
was not achieved at a = 0.05 (p = 0.003). Differences in mortality between zones were
significant (F1,22 = 29.46, p = 0.000), but not between blocks (F3 , 22 = 0.80, p = 0.499). The
results from the Tukey test found that differences observed between zones was significant (p =
0.000), however, a lettered group option could not be generated as there was only one
comparison between zones.

8
7
6

""':' 5
0

~ 4

.£

-

]

3

0

8

.... 2

=
Cll

s::

-I
-2

BWBS I BWBS 2 BWBS 3 BWBS 4

ESSF I

ESSF 2

ESSF 3

ESSF 4

Block Designation

Figure 37. Lodgepo.l e pine seedling mortality (mean and SE) in all blocks. In 2013, the numbers of surviving
seedlings per block were: BWBS I n = 96, BWBS 2 n = 94, BWBS 3 n = 80, BWBS 4 n = 37*; ESSF 1 n = 62,
ESSF 2 n = 66, ESSF 3 n = 68, ESSF 4 n = 43.
*BWBS 4 numbers exclude 15 seedlings in the PIc plot, whkh was disregarded due to ongoing human disturbance.

Three hundred and seventy seedlings were planted in summer 2010 in the BWBS zone, and
another three hundred and seventy seedlings were planted in the ESSF zone. By end of summer
2013, there were three hundred and seven individuals in BWBS plots, and two hundred and
thirty-nine individuals in ESSF plots. The mortality in the BWBS zone occurred between
planting and the first year of measurements. Mean mortality within the BWBS upland blocks
114

was Jess than observations of mortality in ESSF upland blocks. Similarly, mean mortality in the
BWBS 4 block was Jess than that at the ESSF 4 block. Mortality in the " PI c'· lodgepole pine plot
in BWBS 4 was excluded as the plot was abandoned due to continued human disturbance.

6.4 Discussion
Plant growth and biomass differed between blocks for both lodgepole pine and shrubby
cinquefoil. Some results were supported by other research; however other findings were
contradictory to other works on plant growth. The ftndings of this study suggest that optimal
growth for both species considered was not observed in sites with hydric soils, and other plant
species should be considered in wetland reclamation.
6.4.1 Plant Height and Biomass
Lodgepole pine seedlings responded differentially to block soil properties. Total height was
highest in BWBS and ESSF 3 blocks, yet total biomass was greatest in BWBS and ESSF 2
blocks. Shrubby cinquefoil heights were greatest in BWBS and ESSF 3 blocks, however total
biomass was greatest in BWBS and ESSF 1 blocks.

6.4.1. 1 Lodgepole Pine
Growth of pine seedlings between 2012 and 2013 was variable between blocks, between plots,
and within plots. Height of pine seedlings in the ESSF 2 block was the most variable, and mean
plant height was greatest in this block. Soil factors were a significant factor in this zone, in
particular for the ESSF 2 and 3 blocks. It is possible that naturally occurring species such as
frreweed and willow saplings played a role in improved survival and growth of pine seedlings in
the ESSF 2 block, as Castro et al. (2004) demonstrated with the use of shrubs as nurse plants. For
the ESSF 2 block, the mean height of seedlings was higher where species diversity was greater.

115

Average soil moisture values were lowest at the crest position site, where changes in plant height
were highest between 20 12 and 2013, which supports prior research that found a preference of
lodgepole pine for xeric soils (Despain 200 1) although other factors not considered in this
analysis may also contribute to plant height.

Lodgepole pine biomass in the BWBS 4 block was greater for aboveground than belowground.
Other research has noted greater accumulation of aboveground biomass in lodgepole pine in
moist (mesic) sites (Comeau and Kimmins 1989) related to older trees, but this association could
also be important for seedlings in saturated (hygric to hydric) conditions.

Hierarchical regression of pine biomass showed slope was significantly correlated with pine
biomass. Slope was a confounding factor in pine biomass, as biomass was greatest for both
biogeoclimatic zones in south-facing blocks (seven percent slope in BWBS 1, and thirty percent
slope in ESSF 1), however pine biomass was lowest in the BWBS and ESSF 3 blocks (twelve
percent slope in BWBS 3 and twenty-two percent slope in ESSF 3).
Factors affecting lodgepole pine height in BWBS upland blocks were not consistent between
blocks. Bulk density was positively conelated to plant height in BWBS 1, CEC was significant
(positive correlation) in BWBS 2, and moisture was significant (negative correlation) in BWBS
3. Average aboveground biomass at the BWBS blocks was greatest for upland positions. This
contrasts the fmdings of Comeau and Kimmins ( 1989), who noted a higher proportion of
biomass allocation to below ground biomass on drier sites, and higher allocation of biomass to
aboveground production on mesic sites.

Pine allometry considered in this study (total height, stem diameter, and HDR) was, according to
the hierarchical regression model, significantly (p < 0.05) affected by total N (total height),
11 6

available P (total height and HDR), bulk density (total height and stem diameter), and for HDR
only, pH, elevation, and clay percentage. In this study, N was negatively associated with height
as the sites higher inN content were no1th-facing blocks and wetlands, where mean plant height
was lowest; which contrasts with other findings regarding N levels and forest productivity, where
higher N values were positi vely correlated with plant height (Simard et al. 2003). Some research
has found that the effectiveness ofN additions can be compromised by S (Brockley 2000), and
the total S was higher in both wetland blocks. It is more likely that poor plant performance in
wetlands was due to lower tolerance of lodgepole pine to hydric soils.

Available P values were higher in ESSF upland blocks than the BWBS upland and both wetland
blocks. The relationship between P and pine height was positive, however this does not
adequately address the height parameter, as seedlings were taller in the BWBS upland blocks.
Soil bulk density was positively correlated with height and stem diameter; increased bulk density
was associated with increased height and diameter. The lowest bulk density values were
observed in wetlands, where plant growth was lowest, and high bulk densities were noted in
upland blocks, although means were Jess than the critical density where adverse effects to plant
growth in a medium textured soil (> 1.40 g cm-3) are apparent. Growth of lodgepole pine was not
adversely affected by high soil bulk density in this study, and this has been observed in other
lodgepole pine studies (Zabowski eta/. 2000; Kranabetter et a!. 2006).

6.4.1.2 Shrubby Cinquefoil
Height of shrubby cinquefoil varied widely in the ESSF upland blocks, and the tallest seedlings
were noted in the ESSF 3 block, and lowest in the ESSF 2 block. The regression output did not
adequately determine significant factors, although seedling density (species abundance) was
determined significant (p = 0.0 19); total nitrogen, sulphur, potassium, and CEC values were
11 7

higher in ESSF 3 than ESSF 2, however soil temperature was lower in ESSF 3, and moisture
values in 2013 were similar between upland blocks. None of these factors were found to be
significant in the regression of data for the entire study area, although replication of blocks for
slope aspect could have helped understand if these variables were significant between the ESSF
2 block and the ESSF 3 block.
Biomass of shrubby cinquefoil in the ESSF upland blocks was highest in the ESSF 1 block, and
lowest in the ESSF 2 block, although variability in ESSF 1 was higher. Aboveground biomass
accounted for more total biomass than belowground in all upland blocks, but was greatest in
ESSF 1 and ESSF 3. With the exception of slope and species abundance, all factors considered
for analysis were significant fo r aboveground, belowground and total biomass. Notably, total
carbon, total sulphur, CEC, and species richness were negatively correlated with the three
biomass parameters. The effects of these by block could not be determined, and the influence of
soil nut:Iients on biomass may have been skewed by the high values in the ESSF 4 block which
had considerably higher nutrient contents than the upland ESSF blocks.
Nutlition and CEC values for the ESSF 4 block indicated high potential productivity. The soil
moisture regime of this block was classified as hydric, because soil moisture levels were
consistently around 100%. Total carbon was negatively correlated with plant height in this block,
and mean height of plants was low. Total biomass of lodgepole pine was the lowest ofthe
blocks; mo1tality was moderate, and comparable with ESSF upland blocks.
Cinquefoil growth by changes in height between 2012 and 20 13 was minimal (.6. = 12.20 mm) in
the BWBS 4 block. Shrubby cinquefoil is a commonly found species in fen environments (Pojar
1991; Drahovzal et al. 2015), although its suitabili ty as a wetland plant may not be universal

118

(Niswander and Mitsch 1995). One of the factors that could have affected cinquefoil growth in
BWBS 4 was the prevalence ofbluejoint (Calamagrostis canadensis). This species can be
hypercompetitive in disturbed sites, has been demonstrated to adversely affect some plant
species growth (Matsushima et al. 2014), and was the dominant naturally regenerated species in
this block. However, the correlation between shrubby cinquefoil with richness was negative but
not significant, and the correlation with abundance was positive, so this was not a conclusive
factor.

Biomass of shrubby cinquefoil was primarily allocated to belowground in BWBS 4. This find ing
is consistent with other research that suggested greater root than shoot biomass production in
shrubby cinquefoil and other alpine shrubs (Long 2003) in wetland environments. Biomass of
shrubby cinquefoil seedlings was negatively affected by total carbon, sulphur, CEC and species
richness; however, the relationship of these properties to biomass in the wetland block could not
be directly related.

Mixed effects regression results for cinquefoil height showed that soil S and bulk density
affected height significantly. Sulphur values were highest in BWBS and ESSF 3 and 4 blocks,
and bulk density values were lowest in the BWBS and ESSF 3 and 4 blocks. Height of shrubby
cinquefoil seedlings was greatest in BWBS and ESSF 3 blocks. Height averages were lowest in
wetlands, and for uplands plant height was lowest at BWBS and ESSF 2 blocks; soil moisture
was not a significant contributor to plant height.
Cover area of shrubby cinquefoil was significantly influenced by soil moisture, S, CEC, bulk
density, elevation, and soil temperature. Soil moisture was negatively correlated with cover area,
and cover area means were greatest in blocks where the lowest soil moisture averages were

119

observed (21.66 % in BWBS I, and 21.31 % in ESSF 2 block) for each biogeoclimatic zone.
Sluubby cinquefoil grows in a vaiiety of soil moisture conditions; the results of this study
suggest that the cover area growth component performs better in well drained soils in
northeastern B.C.
Shrubby cinquefoil biomass was significantly impacted by all of the variables considered except
available P and effective CEC. Low biomass was correlated with higher soil moisture, observed
in BWBS 3 and both BWBS and ESSF 4 blocks. In upland blocks, greatest biomass averages
were in BWBS and ESSF 1 blocks ( 10.88 g in BWBS 1, 14.82 g in ES SF I ). Soil C and soilS
were negatively associated with cinquefoil biomass, and the mean values of C and S were
highest in BWBS and ESSF 3 and 4 blocks. This does not account for the positive correlation
between biomass and N, mean values for which were also highest in north-facing and wetland
blocks. Elevation was significantly negatively correlated with biomass; this association is not
defmitive, as the ESSF 4 block was at a lower elevation than the ESSF 3 block, where highest
biomass was observed. The values of bulk density and soil pH were not consistently higher in
either the BWBS or ESSF I blocks. The regression model correlated a positive significant
relationship between increased slope and increased cinquefoil biomass, however the ESSF 3
block had the lowest biomass, but the highest slope percentage (thirty percent).
6.4.2 Plant Survival

Pine losses were apparent between planting in 20 I 0 and last measurements in 20 13. There was
not an appreciable difference between mortality in upland and wetland blocks in either zone. The
difference in losses between the BWBS and ESSF zones could be attributed to a nwnber of
factors. Desiccation at sites exposed to wind had a negative influence on survival. The south
facing and crest position sites also had less natural regeneration, reflected by low species
120

richness and diversity of colonizer species within treatment and control plots. Elevation was also
a factor for lodgepole pine mo11ality, with higher mortality in the ESSF zone, where the blocks
were above 1260 m.a.s.l. ; the generally accepted elevation limit for lodgepole pine in northern
B.C. is 1200m (Rehfeldt eta/. 1999).
Cinquefoil losses were not observed during the study period, fmdings consistent with other
research that found high survival (93-1 00%) of cinquefoil seedlings in a variety of growing
conditions (Densmore and Holmes 1987). This species tolerates a wide variety of ecological
conditions and can be persistent in disturbed environments (Elkington and Woodell 1963). Given
the tenacity of shrubby cinquefoil as a colonizer species, and as it has low forage values for
wildlife, the high survival rates of seedlings at the study site are likely typical. At crest and
south-facing blocks, cinquefoil seedlings were occasionally the only surviving species observed
within cinquefoil plots. Planting density may have been a factor, combined with environmental
influences.
Pine mortality regression showed that only effective CEC was significant among the variables
considered for seedling mortality. The relationship was positive, implying that increased CEC
was correlated with increased mortality. This was evident in the BWBS 3 block and the ESSF 4
block, but does not explain high moi1aliry in ESSF upland blocks, where CEC was low, and
mortality was comparable (4.125 to 4.375 plants per block) between blocks. ln the ESSF upland
blocks, there was evidence, which could not be captured, of seedling desiccation from wind
exposure in the south-facing and crest blocks, and small scale mechanical erosion in the ESSF 3
block.

12 1

6.4.3 Limitations
As this was a retrospective study, controls for lodgepole pine could not be established, which
may have shown differences in mortality, growth, and biomass between fertilized and
unfertilized seedlings for each upland block. Limited resources prevented foliar analysis of
destructively sampled seedlings, which could have demonstrated N uptake in plants. Weather
stations that capture wind variables were not established, which could have helped associate
prevailing winds with plant establishment, speci fically for lodgepole pine. The ecologically short
time frame ofthe field components of this study did not allow for determining the potential
effects of time for changes in plant growth and ongoing mortality of seedlings as they mature.

6.5 Conclusion
The primary aim of this study was to observe the response of two plant species planted at sites
where whole tree harvest and substrate disturbance had occurred for installation of pipeline
assets in northeastern British Columbia. The results of this study showed that lodgepole pine
experienced higher mortality in the ESSF biogeoclimatic zone, and that there was greater
variation in plant biomass between upland blocks in the ESSF zone than those in the BWBS
zone. There were no observed shrubby cinquefoil losses during the study period, and biomass
was greater for plants sampled from upland blocks in the ESSF zone than upland blocks in the
BWBS zone.
Future studies and reclamation projects for northeastern B.C. located in the BWBS and ESSF
biogeoclimatic zones should consider using native plant species best suited to site conditions.
The growth of plant species monitored in this study in upland sites suggests that lodgepole pine
and shrubby cinquefoil are suitable for uplands, although elevation and other factors may

122

compromise lodgepole pine survival. In wetlands however, use of vascular plant species that
thrive in wet soils would be preferable.

The results of this study showed that field performance of lodgepole pine was acceptable,
however, mortality rates were higher in the ESSF upland blocks than BWBS upland blocks.
Likewise, cinquefoil field performance was adequate, although biomass was greater in ESSF
upland blocks. Both planted species grew more slowly in wetland blocks, which infers that
species options should be altered for hydric soils. There are opportunities to use other native
species in wetlands, which could be based on locally abundant native plants. Meaningful input
from local First Nations communities would help foster positive relationships between
stakeholders and could also help guide plant species deployment in reclaimed right-of-ways that
include traditional foods and medicinal plants.

123

7.0 Synthesis of Results
This research was commissioned by Shell Canada with a purpose to understand the soil
properties that influence the establishment and growth of plants on a reclaimed pipeline right-ofway in northeastern B.C. Methods included soil sampling of physical and chemical properties,
plant community development within control and planted plots at each research block, assessed
using the Shannon Diversity Index; and plant measurements used to determine field performance
of planted lodgepole pine and shrubby cinquefoil seedlings. Results are found in the preceding
chapters, however, soil physical and chemical properties showed low percentages of plant
available nutrients in south-facing and crest position blocks, and highest in wetland blocks. Plant
species diversity was highest in wetland blocks, and lowest in crest position blocks in both
biogeoclimatic zones. Treatment and slope aspect were significant in species diversity values.
Slope aspect was also influential in plant growth and biomass observations, although the effects
on height and biomass were not directly correlated.

Limitations of this study included Jack of true replicates in the experimental design, which
resulted in pseudoreplication, and the short time frame of the study which may not have captured
site recovery potential. The wind variable was not captured, which could have furthered our
understanding of the effects of wind to site recovery and seedling field performance. The
difference in time since initial disturbance between wetland research blocks may have
contributed to the differences in species diversity between the two wetland blocks in this study.

The significance of the findings to reclamation of pipeline tights-of-way in northeastern B.C.
include the value of retention and careful replacement of soil horizons over pipe trenches; and
that CWD application is beneficial to soil properties. Our results demonstrated that prescriptive
planting can enhance natural regeneration and improve plant species diversity on a pipeline
124

right-of-way. Plant growth findings noted less height accumulation and higher mortality of
lodgepole pine seedlings in the ESSF biogeoclimatic zone than the BWBS biogeoclimatic zone;
and variable biomass allocation to aboveground and belowground. The ESSF biogeoclimatic
zone in northeastern B.C. includes challenging conditions for plant growth, which may be
compounded by the effects of pipeline right-of-way construction in this region.

For future projects, industry should retain CWD wherever possible, as it traps leaf liner and
contributes to higher soil chemical properties. Based on our research, natural regeneration is not
an optimal strategy in BWBS and ESSF zones in northeastern B.C. and planting programs are
strongly recommended to enhance site recovery. It is strongly recommended that industry and
reclamation practitioners apply appropriate plant species in upland and wetland sites, which
reduces plant losses and the need for costly replanting. Industry should also involve stakeholders
(community groups, First Nations, research institutions) prior to commencement of a reclamation
project. This would help foster positive relationships with local communities and First Nations
people, and provide ideas for planting culturally important native plant species. The inclusion of
research institutions would improve the scientific rigour of reclamation trials that can provide
directions for future site management. This would help with site recovery, and provide tools for
site assessment requirements needed by industry to apply for a Certificate of Restoration from
the regulator in B.C. There is also a need to understand plant and wildlife interactions, and
research that examines the interactions would be very beneficial in northeastern B.C.

125

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144

Appendix 1. Soil Analysis
Laboratory/ Analysis
BC MoE Laboratory
Efective CEC

Reference and analysis Description

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Available Phosphorous

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ascorbic acid. Soil Sci. 109 (4): 214-220

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sampling and methods of analysis. 2nd edition. Carter MR, Gregorich EG. 2008.
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Total C, total N

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editors. Canadian society of soil science. CRC Press Boca Raton FL. p I 98

145

Appendix 2. Complete list of species planted in Ojay research blocks
Research Block

Cover Type

Genus

Species

n. Planted 20 I0

BWBS 1

Canopy

Pinus

contorta

Picea

glauco x engelmamzii

Dasiphora

fruticosa

Dryas

drummondii

Hedysarum

boreale

Juniperus

horizontalis

Arctostaphylos

uva-ursi

Aster

al/!_inus

Canopy

Pinus

contort a

Picea

glauco x engelmannii

Understory

Dasiphora

fruticosa

Betula

pumila

Hedysarum

boreale

Aster

al/!_illUS

Pinus

contorta

Picea

mariana

Larix

laricina

Dasiphora

fruticosa

Betula

/!_Umila

100
60
200
1200
23
30
100
60
400
45
23
18
30
40
100
60
400
600
23
40
60
100
340
600
400

Pinus

contorta

100

Picea

glauca x engelmannii

Dasiphora

fruticosa

Hedysarum

boreale

Dryas

drummondii

Understory

BWBS2

Canopy
Understory

BWBS3

BWBS4

Canopy

Understory
ESSF I

Canopy
Understory

ESSF2

Canopy
Understory

Dryas

drummondii

Hedysarum

boreale

Aster

al/!_inus

Pinus

contorta

Picea

glauco x engelmannii

Dasiplzora

fruticosa

Aster

a//!_illUS

Pinus

contorta

Picea

glauco x engelmamzii

Dasiplzora

fruticosa

D1yas

drummondii

Aster

a/pinus

60
400
30
1200
30
100
60
400
1200
30

Arctostaphylos

uva-ursi

N/A

146

ESSF 3

Canopy
Understory

ESSF4

Canopy

Understory

Juniperus

horizontalis

N/A

Pinus

contorta

Picea

glauco x engelmannii

Dasiphora

fruticosa

Betula

pumila

Hedysarum

boreale

100
60
200
400
23

Juniperus

hori=ontalis

18

Arctostaphylos

Lll'O-ursi

Aster

a/pinus

30
40

Pinus

contorta

Picea

mariana

Picea

glauco x engelmannii

Larix

laricina

Dasiphora

fruticosa

B etula

pumila

147

60
60
60
60
600
400

Appendix 3. AJternative Species Diversity Index including Planted Lodgepole Pine and
Shrubby Cinquefoil
Appendix 3A. Cover by Plant Type Including Planted Lodgepole Pine a nd Shrubby
Cinquefoil
Means and standard error (in parentheses) of percent vegetative cover by plant type in Control, Pine and CinquefoiJ
plots. For Control plots n = 9 (aJI blocks); Pine plots BWBS 1,2,3 and ESSF 1,2,3 n = 8, BWBS 4 n = 3, ESSF 4 n =
4; Cinguefoil ~lots BWBS I ,2,3 and ESSF 1.2,3, 4; n = 3 each block, BWBS 4 n = 2.
Other•

BWBSI

Control

1.00 (0.00)

1.38 (1.12)

3.05 (3.15)

4.38 {3.20)

1.00 (0.00)

Pine

3.00 {1.15)

2.11 (1.36)

4.52 (5.29)

4.12 (4.80)

1.33 (0.58)

0

12.60 (10.14}

3.00 {3.51}

2.62 {2.06}

0

Control

0

1.67 (0.58)

2.45 (I. 79)

3.36 (2.11)

3.33 (3.21)

Pine

3.1 1 {1.27)

1.86 (0.69)

6.91 (10. 18)

3.89 (3.34)

1.00 (0.00)

Cinguefoil

0

6.43 (6.80}

2.43 {1.81)

3.86 {2.91)

1.00 (0.00}

Control

0

2.78 (1.39)

11.51 {19.55)

5.18 (5.76)

2.00 (1.00)

5.22 (3.83)

5.14 (6.41)

5.98 (8.51)

5.08 (3.70)

3.33 (1.53)

0

11.67 {8.76}

12.64 {13.372

6.67 (2.89}

4.00 {1.41)

BWBS2

BWBS3

P ine
Cinguefoil
BWBS4

Control

0

1.85 {1.21)

1.50 (0.52)

4.60 (2.28)

3.40 (3.56)

Pine

3.67 (1.15)

6.00 (6.22)

1.60 (0.89)

4.20 (3.56)

7.00 (3.46)

0

4.80 (3.56}

2.25 {0.96}

8.14 {5.24}

6.00 {4.62}

Cinguefoil
ESSF I

ESSF 2

Shrub

Graminoid

Treatment

Cinguefoil

Tree

Herb

Block

Control

1.17 (0.41)

2.50 (3.12)

2.71 (2.52)

2.22 (2.95)

3.00 (0.00)

Pine

2.25 {1.28)

2.25 (2.41)

3. 17 (2.50)

1.65 (0.70)

4.80 (5.85)

Cinguefoil

1.00 {0.00}

12.83 (12.09)

2.75 (2.06}

1.25 (0.50}

1.00 (0.00}

Control

1.25 (0.50)

6.75 (6.95)

2.63 (3.07)

2.00 (1.55)

0

Pine

2.88 (0.99)

7.00 {I 1.90)

6.47(5. 17)

1.46 (0.66)

1.47 (0.74)

0

15.25 (12.532

1.00 (0.00}

1.00 (0.00}

0

Cinguefoil
Control

1.00 (0.00)

2.33 (1.15)

5.56 (5.32)

1.82 (1.60)

0

Pine

2.89 (2.26)

3.15 (2.70)

6.72 (8.61)

6.60 (6.0 1)

1.00 (0.00)

0

7.00{8.16}

8.29 (7.00}

6.00 (5.10}

0

Control

1.00 (0.00)

5.71 (6.72)

9.56 (17.61)

13.80 (16.21)

22.33 (23.63)

Pine

3.60 (2.88)

4.00 (3.70)

5.93 (9.95)

5.85 (7.90)

21.64 (25.96)

Cinguefoil
1.00 {0.00}
7.56 (9.03}
7.15 {9.66}
14.57 {16.45}
• "Other" designation was used for mosses, lichens, and unidentifiable plants.

30.00 (0.00}

ESSF 3

Cinguefoil
ESSF4

148

Appendix 3B. Count by Plant Type Including Planted Lodgepole Pine and Shrubby
Cinquefoil
Means and standard error (in parentheses) of count by plant type observed in Control, Pine, and Cinquefoil plots.
For Control plots n = 9 (all blocks), Pine plots BWBS I ,2,3 and ESSF I ,2,3 n = 8, BWBS 4 n = 3, ESSF 4 n = 4;
Cinguefoil ~lots BWBS 1,2,3, n = 3, BWBS 4 n = 2; and ESSF I ,2,3, and 4, n = 3 each block.
Block
BWBSI

Treatment

ESSF2

2.69 (5.23)

8.78 (9.46)

I 4.56 (13.76)

2.13 (2.47)

2.78 (1.86)

15.70 (18.1 I)

10.94 (13.79)

1.33 (0.58)

0

52.00 ~49.09~

I0.5 (I4.20)

11.84 ~15.86~

0
10.33 (9.50)

Control

0

I.OO (0.00)

7.45 (6.44)

5.68 (5.44)

Pine

I 0.44 (5 .85)

3.7I (4.08)

16.9I (17.61)

9.83 (10.26)

I.50 (1.00)

0

38.14 {43.42~

9.86 (11.41}

10.29 {7.54}

1.00 (0.002

Control

0

2.33 (1.80)

7.69 (8.07)

6.91 (6.92)

4.00 (5.20)

Pine

8.11 (3.48)

4.81 (4.34)

10.12 (14.48)

11.00 (11.66)

3.67 (1.53)

0

40.00 {49.07}

12.57 (13.59}

23.33 {23.09}

1.50 {0.71}

Control

0

1.92 (0.95)

7.69 (8.53)

19.50 (7.59)

2.47 (2.64)

Pine

I 1.33 (4.16)

7.75 (8.42)

5.00 (8.40)

14.60 (10.53)

12.83 (13.63)

0

30.40 {38.37}

5.00 (3.56}

28.57 {13.45}

5.50 (5.20}

Control

2.17(1.17)

5.88 (5.33)

8.86 (8.32)

2.11 (1.62)

20.00 (0.00)

Pine

8.88 (4.49)

6.69 (8.66)

14.43 (12.01)

4.00 (2.76)

18.00(1 7.89)

Cinguefoil

1.00 (0.00)

43.00 {48.92)

9.00 (7.16}

2.5 {1.29)

I 0.00 (0.00}

Control

1.00 (0.00)

9.25 (12.28)

5.50 (5.15)

1.50 (0.84)

0

Pine

10.75 (5.12)

9.00 (6.63)

19.1 I (12.91)

2.31 (1.49)

6.33 (2.29)

0

53.50 {38.77}

3.00 {1.73}

2.00 {I .00)

0

Cinguefoil
ESSF 3

Control

1.00 (0.00)

6.33 (3.21)

I 2.68 (9 .58)

3.00 (1.34)

0

Pine

6.67 (4.21)

8.77 (12.17)

15.00 (16.42)

6.53 (4.31)

1.00 (0.00)

0

26.50 {36.19)

19.86 (17.65~

6.86 {7.52)

0

Cinguefoil
ESSF4

Other*

9.8 (6.2I)

Cinguefoil
ESSF I

Graminoid

1.00 (0.00)

Cinguefoi l
BWBS4

Herb

Control

Cinguefoil
BWBS3

Shrub

Pine
Cinguefoil
BWBS2

Tree

Control

2.00 (1.4I)

4.81 (3.66)

12.72 (16.11)

13.07 (16.80)

2.17 (3.95)

Pine

9.40 (7.30)

7.00 (4.98)

13.20 (17.21)

7.69 (7.89)

I 0.93 (12.96)

Cinguefoil
1.00 (0.00}
I 0.38 (11.72}
20.22 ~25.022
• "Other" designation was used for mosses, lichens, and unidentifiable plants

5.86 {5.482

1.00 {0.00}

149

Appendix 3C. Diversity Index Values Including Planted Lodgepole Pine and Shrubby
Cinquefoil
3

•Control
• Pine
~

• Cinquefoil

·~
Q,l

>

:a
"'
Q,l

·~ 0.5
Q.

en

0

BWBS I BWBS 2 BWBS 3 BWBS 4

ESSF I

ESSF 2

ESSF 3

ESSF 4

Block design ation
Mean Shannon Diversity Index (H') values for Control, Pine and Cinquefoil plots, including planted individuals in
Pine and Cinquefoil plots, all blocks.

150