Canopy Macrolichen Distribution In A Very Wet Oldgrowth Forest Landscape
Of The Upper Fraser River Watershed
David N. Radies
Thesis Submitted In Partial Fulfillment Of
The Requirements For The Degree Of
Master Of Science
in
Natural Resources And Environmental Studies
(Biology)
The University Of Northern British Columbia
June 2008
© David N. Radies
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ABSTRACT
Windward slopes of the inland mountain ranges in British Columbia support a unique
temperate rainforest ecosystem. Continued fragmentation and loss of old-growth forests
in this globally rare ecosystem, has led to calls for the identification of conservation
priorities between remaining stands. This thesis addresses this concern by surveying the
relative abundances of 37 canopy macrolichens over a 70-km2 area of remaining oldgrowth (>140 years) forest in the upper Fraser River watershed, British Columbia,
Canada. To ensure adequate representation of landscape-scale old-growth forest
characteristics, we divided study plots equally among leading tree species and between
broadly defined sites of "wet" and "dry" relative soil moisture. Other variables included:
minimum mean annual temperature, mean annual precipitation, solar loading, and canopy
openness. This thesis integrates two statistical techniques: Nonmetric Multidimensional
Scaling ordination for analysis of lichen assemblages and logistic regression to evaluate
the habitat conditions of a subset of 8 lichen species previously identified as "old-growth
associated".
Ordination suggested that community assemblages were greatly influenced by
both the presence and abundance of bipartite cyanolichens. These communities
correlated well with increasing levels of relative soil moisture, temperature, precipitation,
and canopy openness, with little to no significant effect of tree leading species. Logistic
regression models identified relative soil moisture and temperature in all parsimonious
models. Leading tree species, in combination with moisture and temperature, were
important factors explaining the presence or absence of 5 of 8 modeled lichen species.
ii
The results of this thesis emphasize the importance of maintaining representative areas of
old-growth forests that are potentially less prone to natural disturbances such as fire. Of
concern to the maintenance of lichen populations in old-growth inland temperate
rainforests is the continued forest harvesting of low-elevation water-receiving sites. It is
recommended that the conservation of these wet topographic positioned areas be
identified spatially to meet remaining provincially set old-growth threshold targets for the
purpose of maintaining biological diversity and ecological integrity.
in
TABLE OF CONTENTS
Abstact
ii
Table of Contents
iv-v
List of Tables
vi-vii
List of Figures
vii-x
Acknowledgments
Xi
Preface
xii
Introduction
1
Chapter One: Not all old-growth is equal: Ecological attributes and lichen
3
biodiversity in an inland temperate rainforest landscape
Introduction
3
Methods
7
Results
13
Discussion and conclusion
15
Chapter Two: Parallels between old-growth forest retention targets and the
23
children's game Kerplunk!
Introduction
23
Methods
26
Results
31
Discussion and conclusion
32
Works Cited
39
Tables
49
IV
Figures
62
v
LIST OF TABLES
Table 1-1. Macrolichen presence/absence by number of sites containing each species and
abundance distribution (in brackets) in the upper Fraser River watershed. Abundances
denote frequency of occurrence of each species based on a three point scale: very low
equals 1-3 thalli, low equals 3-10 thalli, and common equals more than 10 thalli per site.
One exception, is L. pulmonaria*, which was measured by number of handful sizes (10 x
20 cm2) as opposed to thalli measurements.
Table 1-2. Multiple linear regression estimates for the log-transformed environmental
variables temperature, precipitation (mean minimum temperature, March to October),
solar loading, canopy openness, relative soil moisture, and basal area of cedar (Cw),
hemlock (Hw), spruce (Sx), and fir (Sf) calculated against Axis 1 (R2 = 0.548, f-ratio =
5.529, P < 0.001) and Axis 2 (R2 = 0.656, f-ratio = 8.701, P < 0.001) ordination scores (n
= 51)
Table 1-3. Mean and standard deviation of stand variables. N = 27 and 26 respectively for
dry and wet broad relative soil moisture (BRSM) stands in the upper Fraser River
watershed.
Table 1-4. Predicted best model sets (> 0.1 AICcw) for presence of the old-forest
associated macrolichens and receiver operating characteristic (ROC) results for best
models in the upper Fraser River watershed. Abbreviations for model variables are as
follows: broad relative soil moisture (BRSM); leading tree species (LEAD); canopy
openness (OPEN), mean annual precipitation (PRECIP) and; mean minimum
temperature, March - October (TEMP). Abbreviations in brackets —cedar (Cw),
hemlock (Hw) and wet BRSM (wet) — represent categorical variables with greatest
influence.
Table 2-1. List of macrolichen species and abbreviations surveyed for in the upper Fraser
River watershed.
Table 2-2. Independent variable abbreviations and categorical coding (in brackets) used
to predict the probability of occurrence of the 8 'old-growth dependent' lichen species
(see Radies et al. 2008) including Cavernularia hultenii, Lobaria retigera, and Nephroma
occultum.
Table 2-3. 13 models tested for each species in the upper Fraser River watershed.
Table 2-4. Site sampling breakdown in the upper Fraser River watershed.
Table 2-5. Ecosystem representation as a % of total area of ICHvk2 biogeoclimatic zone
in the upper Fraser River watershed of old-growth forests with wet versus those with dry
broad soil moisture regime status and the proportion of these old-forest stands that
currently falls in the non-timber harvesting landbase (NHLB), and in two types of
protected areas: old-growth management areas (OGMA), and provincial parks. ROGC =
Remaining Conifer species (consisting mainly of Abies lasiocarpa). Total forested area of
ICHvk2 is 130,571 ha. Base year = 2001.
VII
LIST OF FIGURES
Figure 1-1. Landscape distribution of old-growth cedar, hemlock, and spruce-leading
forests (separated by both wet and dry broad relative soil moisture conditions) in the very
wet cool Interior Cedar Hemlock (ICHvk2) and adjacent very-wet cool Sub-Boreal
Spruce (SBSvk) biogeoclimatic zones of the upper Fraser River watershed. Forests north
of the Fraser River are part of the Rocky Mountain formation, while forests south of the
Fraser River are part of the Columbia Mountain formation. Insert 1 indicates study
location in British Columbia, Canada. Insert 2 and 3 identifies old-growth forest type on
north and south-facing aspects of Driscoll ridge respectively. Reference points indicate
plot-sampling locations.
Figure 1-2. Overlay of species abundance in the upper Fraser River watershed in 2005 on
stand ordinations for the tripartate macrolichen Lobaria pulmonaria, and the bipartate
cyanolichens: L. retigera, Sticta fuliginosa, Nephroma isidiosum, Nephroma occultum,
and Pseudocyphellaria anomala
Figure 1-3. Coefficients and 95% confidence intervals of independent variables for each
of the eight "old-growth associated" lichen species in the upper Fraser River watershed
generated using logistic regression. Abbreviations of variables as follows: dry relative
soil moisture (dry); wet relative soil moisture (wet); canopy openness (Densio); mean
minimum temperature (Temp); Mean annual precipitation (Precip); solar loading (Solar);
cedar-leading (cw); hemlock-leading (hw); and spruce-leading (sx).
Vlll
Figure 2-1. Distribution of Interior Cedar Hemlock wet and very wet biogeoclimatic
variants within the Inland Temperate Rainforest (ITR) boundary (Inset). Abbreviations
as follows: w = wet; v = very wet; k = cool; c=cold. From Craighead and Cross 2004.
Figure 2-2. Clear-cut logging activity in past 50 years in the northern portion of the ITR.
ICHwk and vk forests in colour. From Craighead and Cross 2004.
Figure 2-3. Distribution of remaining class 8 (140-250 years) and class 9 (250 years or
older) old-growth forests in the ICHwk and ICHvk. From Craighead and Cross 2004.
Figure 2-4. Clear-cut logging in the past 50 years in and surrounding the ICHvk2 and
Sub Boreal Spruce very wet (SBSvk) biogeoclimatic zones. Portion of SBSvk that
appears unharvested is Timber Forest License 30, in which logging activity was
unavailable at time of writing. From Craighead and Cross 2004.
Figure 2-5. Location of study sites. Note that the ICHvk2 has been more recently been
divided into the ICHwk4 and ICHvk2 (see Fig. 2-6).
Figure 2-6. Remaining coniferous leading forests greater than 140 years and distribution
by dominant tree species. "Other species" is mostly leading in Abies Lasiocarpa.
Figure 2-7. Sample plots used for data collection: A. Stand Structure Plot (r=17.84m); B.
Lichen Plot - area inside the 40m x 100m (0.4ha) rectangle. Locations of densiometer
measurements are identified by point locations (square point indicating plot centre).
Figure 2-8. Ordination distance matrix, identifying macrolichen species presence and
absence in wet and dry Broad Relative Soil Moisture (BSMR) sites by tree leading
species. Codes are as follows: Cw = cedar-leading; Hw = Hemlock leading; Sx =
Spurce leading.
IX
Figure 2-9. Predicted distribution of wet and dry BSMR old-growth forests leading in
Thujaplicata or Tsuga heterophylla in the ICHvk2. Based on data from 2006.
Figure 2-10. Predicted probability of occurrence (very low, low, medium, high, very
high) for Cavernularia hultennii in the ICHvk2 biogeoclimatic subzone in the upper
Fraser River watershed. See Fig. 2-1 for geographic placement of area.
Figure 2-11. Predicted probability of occurrence (very low, low, medium, high, very
high) for Lobaria retigera in the ICHvk2 biogeoclimatic subzone in the upper Fraser
River watershed. See Fig. 2-1 for geographic placement of area.
Figure 2-12. Predicted probability of Nephroma occultum occurrence (very low, low,
medium, high, very high) for in the ICHvk2 biogeoclimatic subzone in the upper Fraser
River watershed. See Fig. 2-1 for geographic placement of area.
x
ACKNOWLEDGEMENTS
First, I would like to thank all my friends and family for their encouragement, patience
and support. I am particularly grateful to: M.E. Gauthier, C. Helenius, J. Kelly, D.
Khurana and C. LeBoutier for assistance with fieldwork and; D. Coxson, S. Stevenson, P.
Sanborn and C. DeLong as supporting members of my committee. C. Johnson and K.
Konwiki for all their technical support in developing the predictive models and maps. T.
Goward for assistance with lichen identifications; Baden Cross (Applied Conservation
GIS mapping) and the Valhalla Wilderness society for providing the Inland Temperate
Rainforest Maps (Figures 2-1 to 2-4). The Canadian Forest Service supplied climate
data. The Sustainable Forest Management Network, the B.C. Forest Science Program,
Mountain Equipment Coop, and the University of Northern B.C provided funding.
XI
PREFACE
Chapter 1, "Not all old growth is equal: Ecological attributes and lichen
biodiversity in an inland temperate rainforest landscape''' is currently in submission as a
co-authored manuscript of the same title to the journal "Ecological Applications". The coauthors of this submission (listed in order of contribution) were David N. Radies, Darwyn
S. Coxson, Chris J. Johnson, and Ksenia Konwicki. Darwyn Coxson and David Radies
jointly wrote the "Ecological Applications" manuscript, with additional contributions from
Chris J. Johnson, and Ksenia Konwicki. Logistic regression analysis was conducted by
David Radies and Chris Johnson, GIS queries and mapping was conducted by Ksenia
Konwicki and David Radies, and ordination analyses and related statistical testing was
carried out by Darwyn Coxson.
The analysis of the data sets presented in Chapter 2 "Parallels between old-growth
forest retention targets and the childrens game Kerpluck!" was respectively conducted by
Ksenia Konwicki and David Radies (GIS queries and mapping) and Darwyn Coxson
(distance matrix). Writing responsibilities for Chapter 2 reside solely with David Radies.
David Radies provided the primary data set on which the analysis conducted for
Chapter 1 and 2 above were based, using field data collected under his M.Sc. thesis project.
The data sets presented in this thesis were prepared under contract for the Forest
Science Program of British Columbia by the University of Northern British Columbia
(Darwyn Coxson, Principal Investigator), which retains copyright in these data sets for the
purposes of meeting contract deliverables with the British Columbia Forest Science
program.
INTRODUCTION
In British Columbia, Canada, water creates two distinct old-growth mountain
forest ecosystems — described as coastal and inland temperate rainforests. These
temperate mountain ecosystems trap massive volumes of snow at higher elevations in
long winter periods, slowly releasing a migration of ground water beneath coniferous
forests from tree line to valley bottom far into the summer months. Importantly, this
movement of melt-water, in combination with rainfall, is not equally distributed either
between these two mountainous ecoregions or within them. Soil water is orchestrated by
a vast array of climatic, topographic and edaphic conditions, which create a broad range
of soil moisture conditions that affect the natural disturbance regime and forest conditions
at a variety of scales.
Continued loss of habitat in primary temperate rainforest in British Columbia is of
concern. The provincial government of BC continues to allow clear-cut forest harvesting
in both its coastal and inland temperate old-growth rainforests due to the fact that
approximately half of old-growth mountain forests will remain in their natural state.
However, these remaining old-growth forest stands are primarily in forested regions
considered "inoperable". Inoperable old-growth temperate rainforest tend to reside in
mountain regions that are considered not economically viable from a forest industry
perspective mostly due to geographic positioning (i.e. steep mountain topography) and/or
timber quality or in areas restricted from harvest (i.e. provincial parks). Given that it is
unlikely that inoperable old-growth will have the same ecological attributes as operable
old-growth landscapes, it is reasonable to determine whether retaining inoperable areas of
Radies 1
old-growth forest will maintain ecological function and integrity of these globally
significant ecosystems.
This thesis — as one part of a required body of scientific work needed to address
ecological differences between operable and inoperable old-growth forests — inquires as
to whether canopy macrolichen diversity will be impacted if timber harvesting in inland
temperate old-growth rainforests does not recognize differences among site or stand
conditions within the biogeoclimatic subzone scale. To answer this question, the
following four objectives were identified: 1. to examine the influence of dominant
ecological characteristics (i.e. soil moisture, temperature) and forest composition (i.e. tree
leading species, canopy openness) on arboreal foliose macrolichens as communities and
as individuals — in particular "old-growth associated" lichens — in the Inland Temperate
Rainforests of the upper Fraser River watershed; 2. to compare and contrast the
ecological requirements of lichen communities versus individual lichen species; 3. to
examine the effectiveness of predicting the presence of "old growth-associated" arboreal
lichens using coarse filter landscape attributes applicable to GIS; and 4. to compare and
contrast stand and site attributes within and outside the timber harvesting landbase to
determine if old-growth forests considered inoperable are capable of maintaining arboreal
macrolichen diversity at the landscape scale
I have divided this thesis into two main chapters, the first is a multi-authored
paper submitted to a scientific journal intended for an international scientific audience
and the second is intended for provincial forest managers, biologists, politicians and the
general public. It is my hope that this work evokes a deep respect for the complex
ecology of old-growth temperate rainforests, of which we know so little.
Radies 2
CHAPTER 1: NOT ALL OLD-GROWTH IS EQUAL: ECOLOGICAL
ATTRIBUTES AND LICHEN BIODIVERSITY IN AN INLAND TEMPERATE
RAINFOREST LANDSCAPE
INTRODUCTION
Wet-temperate rainforest ecosystems are widely recognized as an important
repository of biodiversity, particularly for organisms that live within the forest canopy
(Kitching et al. 1993, McCune et al. 2000, Castellon and Sieving 2007). In British
Columbia (B.C.), important steps have been taken for conserving large regions of coastal
temperate rainforests (Coast Information Team 2004). However, a second major wettemperate rainforest ecosystem is found on the windward slopes of interior mountain
ranges. This inland temperate rainforest (ITR) has many unique characteristics, including
globally significant assemblages of canopy lichens (Goward 1994, Arsenault and Goward
2000, Goward and Spribille 2005), serving as habitat for endangered populations of
mountain caribou (Stevenson et al. 2001), and supporting headwater spawning runs for
many of the Fraser River salmon populations (Kew 1992).
A major difference between coastal and inland temperate rainforest ecosystems in
B.C. is that ITR ecosystems receive approximately half the annual precipitation of the
former. Therefore, the development of "rainforest" attributes in the ITR is more
dependent on patterns of snowmelt that influence ground moisture conditions. Eng
(2000) noted that stands located on cool north facing slopes showed a near 10-fold
reduction in stand destroying fire frequency compared to stands associated with warm
south facing aspects in inland mountainous forests of central B.C. Beaty and Taylor
Radies 3
(2001) reiterated this influence of aspect and further identified a reduced fire frequency in
lower slope, water-receiving topographic positions. DeLong (1998) reported that annual
fire return intervals in wet montane forests of the upper Fraser River watershed ranged
from 244 to over 1600 years while Sanborn et al. (2006) found a median time since fire in
wet inland temperate rainforests between 800-1200 years These results suggest that
disturbance processes in the wettest portions of ITR are more similar to coastal temperate
rainforests, where single-tree gap dynamics dominate due to tree age (Lertzman et al.
2002), while in drier parts of the ITR, stand replacing fires will occur, yet infrequently.
In the upper Fraser River watershed, this resistance to fire in wet toe-slope valley
bottom positions has favored the development of forest stands that contain western red
cedar {Thuja plicata) trees of exceptional age (i.e. 1000 years old) and stature (i.e. 3
meters in diameter) (Benson and Coxson 2002). Goward and Arsenault (2000) identify
some of these forest stands as "antique": sites where the last major stand replacement
disturbance event, such as fire, happened well before the current generation of trees
established. Preliminary studies (Goward 2003) in the upper Fraser River watershed
have suggested that forest stands in water-receiving toe-slope positions contain highly
diverse communities of arboreal lichens.
Human impacts on ITR watersheds of the upper Fraser River valley have occurred
mostly in valley-bottom locations. Forest harvesting (and accidental fires) accompanied
railroad development along the upper Fraser River valley in the early 1900s, followed by
highway development on north facing slopes in the mid 1960s. Thus, while DeLong
(2007) identified a natural range of variability between 76-84% in the cover of oldgrowth forests in wet mountain trench ecosystems of the upper Fraser River watershed,
Radies 4
current cover estimates of approximately 64-68% (Anonymous 2005) suggest that these
old forest types are under-represented relative to natural disturbance regimes. These
trends parallel those in coastal wet temperate rainforests, where historical harvesting has
similarly targeted old-growth forests in valley bottom locations (Moola et al. 2004)
Current landscape level management policies in the upper Fraser River watershed
specify an old-growth management threshold of no less than 53% old-forest cover greater
than 140 years of age (Anonymous 2004). This target, which overlooks stand or site
variability within the biogeoclimatic subzone unit, does not necessarily ensure that oldforest stands of high biological value will be retained in future landscapes. Indeed, the
opposite may be true, in that the placement of transportation corridors through toe-slope
stands in the upper Fraser River watershed has resulted in disproportionate clear-cut
harvesting of old-forest stands in surrounding valley bottom positions.
In the U.S. Pacific Northwest and elsewhere canopy macrolichens have been used
as indicators of stand age (Hyvarinen et al. 1992, Campbell and Fredeen 2004) and
environmental conditions on forested landscapes (McCune et.al. 2000, 2002, Liden and
Hilmo 2005). Furthermore, macrolichens have proven to be useful indicators of total
lichen diversity (Bergamini et al. 2005) and other taxa (Negi and Gadgil 2002) when
applied appropriately (sensu Niemi and McDonald 2004). Therefore, we suggest that a
landscape-level assessment of canopy macrolichens in ITR, could provide major
advances in our understanding of the role old-growth site and stand structural attributes
contribute to the biological integrity of these ecosystems.
We addressed this premise by evaluating the composition and abundance of
canopy macrolichens in relation to structural and site attributes in 53 old-forest stands,
Radies 5
located within a 70-km2 area of the upper Fraser River watershed. Landscape-level
sampling was stratified to ensure equal representation of wet and dry broad relative soil
moisture (BRSM) site conditions. Reasons for stratifying our study design by soil
moisture are twofold. First, soil moisture affects the ecology of forested landscapes
including the development and structure of forest stands (Lertzman 2002, Spies et al.
2006), plant species numbers (Zinko et al 2005), and underlying ecological processes
(Pastor and Post 1986, Turner 1989). Second, relative soil moisture is a forest
management tool, applied from site-specific forest practices (DeLong et al. 2003) to
coarse-filter landscape-level planning implementation using G.I.S. technology
(Anonymous 1999, Iverson et al. 2000). We further stratified each of the two BRSM
categories into an equal number of "cedar-" (Thuja plicata), "hemlock-" (Tsuga
heterophylla), and "spruce-" (Picea glauca x P. engelmannii) leading stands, identifying
the potential influence of substrate on lichen diversity (Goward and Arsenault 2003).
Our analysis uses ordination approaches to examine community level responses of
canopy lichens, and logistic regression to examine autecological responses of a subset of
individual species identified by Goward (1994) as "old-growth associated".
Our research is intended to provide guidance on the interpretation of canopy
macrolichens as indicators of both microclimatic conditions and forest stand continuity in
old-growth inland temperate rainforests. We also assess the importance of site and standlevel old-growth representation for managing sensitive macrolichen species, which may
be a gap in current ecosystem-based management strategies (Anonymous 2004, Coast
Information Team 2004, Price et al. 2008). The ecology and conservation status of
lichens, as well as the range and magnitude of threats facing them are not well understood
Radies 6
(Fazey et. al 2005). This study represents the first landscape-level analysis of arboreal
lichen habitat attributes in old-forest stands of the inland temperate rainforest of western
North America. There is a pressing need for this type of study, given the conversion of
representative valley bottom temperate rainforests to plantation management and the
attendant loss of old-growth associated species.
METHODS
Study Area
The study area is located in east-central B.C., Canada, in the upper Fraser River
watershed (Fig. 1-1, inset 1). This region is part of the inland rainforest formation or
"interior wet-belt" (Stevenson et al. 2001) of the Rocky and Columbia mountain
formations that consists of: high elevation wet and very wet Engelmann Spruce Subalpine Fir (ESSF) forests (in blue) (between 49° - 57° latitude); mid to low mountain
elevation, wet and very wet Interior Cedar-Hemlock (ICH) forests (in green) (between
51° and 54° latitude); and extreme valley bottom locations of the very wet-cool Sub
Boreal Spruce (SBSvk) forests (in yellow) (between 53° and 55° latitude).
We focused on forests in the Slim variant of the very wet-cool ICH
biogeoclimatic subzone (ICHvk2) (DeLong 2003), and to a limited extent, adjacent
valley bottom forests within the SBSvk (Figure 1). ICHvk2 forests are dominated by
western redcedar {Thujaplicatd), hereafter referred to as cedar and western hemlock
(Tsuga heterophylla), hereafter referred to as hemlock, with some Douglas-fir
{Pseudotsuga menziesii), hybrid white spruce {Picea engelmanni x P. glauca), hereafter
referred to as spruce, and sub-alpine fir {Abies lasiocarpa), hereafter referred to as fir.
SBSvk forests are dominated by spruce and fir (Fig 1-1).
Radies 7
The distribution of remaining areas of old forest in the ICHvk2 and SBSvk varies
greatly across the upper Fraser River watershed (Fig. 1-1). Many of the tributary valleys
have been heavily logged and have little remaining old-forest cover. Furthermore, based
on location of most logging clearcuts, it is evident that harvesting patterns have targeted
low elevation wet broad relative soil moisture (BRSM) sites, most notably spruce and
secondly cedar In general, wet BRSM are primarily found on north-facing slopes in mid
to lower valley positions, though they occupy a more topographically restricted band in
toe-slope positions on south facing slopes (i.e. compare inset 2 and inset 3, Fig. 1-1).
Wet hemlock-leading sites are more spatially confined, often occurring in lower valley
topographically flat positions with standing surface water. Spruce-leading forests, both
wet and dry, are found both in upslope topographically cold locations and extreme low
elevation sites, in part, subject to cold air pooling.
Mean annual precipitation of the ICHvk2 is 839.8 mm (374.3 mm in summer and
465.5mm in winter) with a mean summer temperature of 14.7 °C and a mean winter
temperature of-12.1°C. Recorded mean annual snowfall is 306.8mm persisting on the
ground for up to 8 months of the year (Reynolds 1997). Slow-melting snow packs in
higher mountain elevations tends to keep soil moisture levels high in the ICH during the
summer months (Ketcheson et al. 1991), particularly on north-facing aspects.
Study Design
Field data were collected in summer 2004 and 2005. We randomly selected 53
GIS polygons to sample from a total of 120 candidate polygons (Fig. 1-1). Selection
criteria for eligible polygons (hereafter called stands) included: a) location in the ICHvk2
and in the adjacent SBSvk (within 5 km of the ICHvk2) biogeoclimatic subzones; b)
Radies 8
forest greater than 140 years in age; c) cedar, hemlock, or spruce leading; d) 500 m or
less from road access (for logistical purposes) and; e) at least 50 m from cutblock edges,
riparian areas, and deciduous forest types. We used the B.C. Ministry of the
Environment Predictive Ecosystem Mapping (PEM) database (an ecosystem mapping
database conducted at a 1:50,000 scale; see Anonymous (1999)) and the B.C. Ministry of
Forests Vegetation Resources Inventory (VPJ) database (a forest inventory mapping; see
Anonymous (1998)) to identify candidate polygons that met our selection criteria.
Sampling within old growth forests was stratified to ensure representation from
each of cedar-, hemlock-, and spruce-leading stands (using VRI), and from stands
representing both wet or dry BRSM conditions (using PEM). At each stand, we laid out
2 plots that shared a common centre. The lichen assessment plot was a rectangular
survey area 40m x 100m, with the long axis parallel to the slope contours to avoid
marked topographic changes. Each plot was assessed for 37 possible arboreal foliose
lichens (checklist adapted from Goward et al. 1994) using survey methods of McCune et
al. (2000). Each macrolichen species observed was given an abundance rating between 0
and 4 (with the exception of Lobariapulmonaria): 0 = absent, 1 = rare [1-3
individuals/plot], 2 = uncommon [4-10 individuals/plot], 3 = common [>10 individuals],
4 = very abundant [covering more than half of available substrates]. For L. pulmonaria,
similar categorical measurements were made, but because of its ubiquity and high
abundances in this ecosystem, we used a measure of "hand-size" (approximately 10 x 20
cm2)/lichen plot in place of "individuals/lichen plot". Melanelia and Parmelia lichens
were surveyed at the genus level.
Radies 9
The stand structure plot was a circular plot with a radius of 17.8 m. The purpose
of the stand structure plot was to provide more detailed information on the structural
components of the forest stand structure and on Relative Soil Moisture (RSM) conditions.
Diameter at breast height (DBH) (1.3 m) was measured for all stems greater than 16.5 cm
DBH, categorized by live and dead stems and identified by tree species. RSM of each
stand was classified on a seven point scale using the moisture regime key in DeLong
(2003), which incorporates measurements of slope gradient, meso slope position, aspect
and soil texture. Soil samples for texture analysis were obtained from within a soil pit
dug to approximately one meter at plot centre.
At each of 13 locations, one in the centre and two on each of the six transects,
four replicate measurements of canopy openness were taken using a spherical
densiometer. These measurements at each location were taken at 90° intervals, and then
averaged. We subsequently pooled all 13 averages to obtain the overall "openness" of
the stand.
Predicted mean annual precipitation and temperature for each stand was obtained
from the Canadian Forest Service (CFS) regional climate database (Hutchinson 1995).
We used mean monthly minimum temperature for the months March-October in our
analysis; this reflected the seasonal time period during which most lichen growth occurs
(Coxson and Stevenson 2007). Potential solar insolation was calculated using SAGAGIS Version 2.0 (Scilands GmbH, Gottingen, Germany) solar radiation model.
Data Analysis
Nonmetric multidimensional scaling (NMS) ordination was used to examine
trends in lichen community composition across stands (PC-ORD V. 4.0, McCune and
Radies 10
Mefford 1999). We then used a general linear regression model to evaluate the following
variables against ordination scores for Axes 1 and 2: temperature (TEMP), precipitation
(PRECIP), solar insolation (SOLAR), canopy openness (OPEN), relative soil moisture
(RSM), and basal area of cedar (BACw), hemlock (BAHw), spruce (BASx), and
subalpine fir (BASf). Variables were tested for multicollinearity (Stata Corporation
2002, College Station, Texas). For all variables, we used a tolerance score of < 0.2 to
indicate significant multicollinearity (Menard 2002).
We used logistic regression to identify important environmental factors that
influenced the distribution of lichens observed in our sample plots. We fit logistic
regression models to presence-absence data for Cavernularia hultenii, Lobaria retigera,
Nephroma isidiosum, Nephroma occultum, Platismatia norvegica, Peltigera collina,
Sticta fuliginosa and Sticta oroborealis, species previously identified as old-growth
associated by Goward (1994). Independent variables assessed for each lichen species
included: categorized Broad Relative Soil Moisture (BRSM) categorized as wet or dry
(see below), canopy openness (OPEN), average minimum temperature (TEMP), average
annual precipitation (PRECIP), solar insolation (SOLAR), and leading tree species
(LEAD, categorized as Cw, Hw, or Sx; see below)
Plots were classified as wet when the BRSM was above 4 on the 7 point relative
soil moisture scale, and dry if the BRSM was less than 4 (corresponding to mesic or
submesic sites in DeLong's (2003) moisture regime key). When stands were classified as
a 4 (mesic), vegetation and soil characteristics were used to separate wet versus dry
BRSM categories. When identifying the leading species (LEAD), a stand was
determined leading in cedar (Cw), hemlock (Hw), or spruce (Sx), based on the tree
Radies 11
species that had the highest Basal Area in the stand (to be consistent with VRI
classification methodology).
We tested thirteen combinations of independent variables that served as plausible
explanatory hypotheses for the distribution of each lichen species: l.BRSM X OPEN X
TEMP X PRECIP; 2. BRSM X OPEN X TEMP X SOLAR; 3. BRSM X PRECIP; 4.
BRSM X TEMP; 5. LEAD X BRSM; 6. LEAD X OPEN X TEMP; 7. LEAD X OPEN X
PRECIP; 8. LEAD X OPEN X SOLAR; 9.LEAD X PRECIP; 10. LEAD X TEMP; 11.
OPEN X PRECIP X SOLAR X TEMP; 12. OPEN X PRECIP; 13.OPEN X TEMP. We
used Akaike's Information Criterion with a correction for small sample size (AICC)
(Johnson and Omland 2004) to identify the most parsimonious logistic regression model.
All AICC values were subtracted from the lowest AICC value in each model set to derive
the AIC difference (AICC dif). We then calculated the AICC weights (AICcw) and
interpreted this value as the approximate probability that the model with the largest value
was the most parsimonious of the set (Johnson and Omland 2004). We calculated the
area under the Receiver Operating Characteristic (ROC) curve for the top-ranked models
(Munoz and Felicisimo 2004). ROC scores allowed us to evaluate the ability of the most
parsimonious model to predict the distribution of lichens on the landscape.
We used Multi-Model Inference (MMI) to determine the relative importance of
the predictor variables for each species (Johnson and Omland 2004). MMI uses the
AICcw to average the coefficients from all variables within the set of models for each
lichen species and thus accounts for variation attributed to model selection uncertainty.
We used 95% confidence intervals, corrected for model selection uncertainty, to assess
the strength of effect of each predictor covariate on the dependent variable.
Radies 12
RESULTS
Of the 37 species and 2 genera {Melanelia spp. and Parmelia spp.) of arboreal
lichens surveyed within the 53 study plots, 18 of the 19 cyanolichens were either more
frequent and/or occurred with greater abundance in stands that had wet BRSM conditions
(Table 1-1). The only exception to this pattern was the cyanolichen, Sticta wrightii
which occurred rarely (less than 4 thalli present) in 3 sites, in which 2 of the 3 sites were
classified as dry BRSM. The chlorolichens occurred with relatively even frequency and
abundance between stands with wet and dry soil moisture conditions, the noticeable
exception being Cavernularia hultenii, which had a much higher frequency of occurrence
in stands with wet BRSM conditions.
Stand ordinations showed clustering of bipartite cyanolichens in the upper left
quadrant of the plot (Fig. 1-2). This included regionally rare species such as Lobaria
retigera and Nephroma occultum and the more commonly abundant bipartite
cyanolichens such as Nephroma isidiosum, Pseudocyphellaria anomala, and Sticta
fuliginosa. The tripartite cyanolichen Lobaria pulmonaria, was found widespread
throughout the ordination, although it displayed some tendency of increasing abundance
in the upper left quadrant of the plot (Fig. 1-2). Most of the chlorolichens were widely
distributed, showing no strong placement preference along the two ordination axes.
Temperature and precipitation were significantly correlated with both axis 1 and
axis 2 ordination scores (Table 1-2). When fit to a linear regression, data for Axis 2
demonstrated the best fit (R2 = 0.656), with the variables relative soil moisture (P =
0.002), temperature (P = 0.005), canopy openness (P = 0.010), precipitation (P = 0.020),
and basal area of spruce (P = 0.028) accounting for a significant proportion of the
Radies 13
variation. Only temperature (P = 0.001) and precipitation (P = 0.021) were correlated
with Axis 1 ordination scores (R2 = 0.548). Mean annual temperature, relative soil
moisture, basal area, and canopy openness co-varied (Table 1-3).
When fitting and assessing the suite of logistic regression models we noted few
similarities among the 8 old-growth associated lichen species (Table 1-4). The
exceptions were N. occultum and C. hultenii, for which the best predictive models
consisted of leading tree species and wet or dry BRSM status (although these two lichens
selected for different leading tree species). The variables associated with the most
parsimonious models for each lichen species were: temperature (6 species), leading tree
species (5 species), relative soil moisture condition (4 species), openness (4 species), and
precipitation (1 species) (Table 4). ROC scores ranged from 0.7175 {P. norvegica) to
0.9183 (N. isidiosum), indicating a good to excellent fit for each of the lichen species
(Table 1-4).
Averaged coefficients suggested that all variables, other than precipitation and
insolation, had some influence (positive or negative) on the distribution of one or more
old-growth associated lichen species (Fig. 1-3). Dry BRSM status had a 0 to negative
effect on the presence of the eight lichen species, and wet BRSM status showed positive
effects (both with relatively small confidence intervals). Canopy openness (OPEN)
showed 0 or slightly positive effects. The temperature variable had the largest effect on
the distribution of N. isidiosum or 5*. oroborealis, though confidence intervals were quite
large. In combination with temperature and/or BRSM, L. retigera, P. norvegica, and S.
oroborealis showed greatest affinities to stands leading in hemlock and to a lesser degree
cedar. C. hultenii, a chlorolichen, was related almost exclusively to hemlock and
Radies 14
negatively to both cedar and spruce leading stands whereas N.occultum, a cyanolichen,
showed preference to cedar dominated forests and a negative association with both
hemlock and spruce dominated forests. Spruce had either no effect or a negative
influence on the presence of the 8 lichen species we tested. As with temperature,
confidence intervals were often quite large for leading tree species (Fig. 1-3).
DISCUSSION
The first major question of our study was whether distinct assemblages of oldgrowth dependant foliose macrolichens were distributed equally across an old-growth
forest landscape of Inland Temperate Rainforest (ITR). A homogenous distribution of
lichens would suggest that arboreal lichens do not respond to stand characteristics other
than the criteria of reaching ages of 140 years or older. Our ordination plots show a clear
assemblage of lichen species within a representative subset of old-growth forests greater
than 140 years of age. These assemblages occurred mostly at low elevations (as lower
elevations in the temperature models were identified by warmer temperatures) with
topography that favored the accumulation of soil moisture. Of the old-forest associated
species identified by Campbell and Fredeen (2004) the following more regionally rare
species, C. hultenii, L. hallii, N. isidiosum, andN. occultum, were either limited to or
more frequent and abundant in stands with wet BRSM conditions. Other old-growth
associated lichens designated by Campbell and Fredeen (2004), such as H.vittata, L.
scrobiculata, N. helveticum, N. parile, P. anomala and S. fuliginosa, were more widely
distributed in our old forest stands, but were still far more abundant on wet BRSM sites.
A third set of old-growth associated lichens identified by Campbell and Fredeen (2004),
Radies 15
chlorolichen species such as Hypogymnia rugosa and P. norvegica, were widely
distributed in both wet and dry stands greater than 140 years of age.
From these results, we can identify an appropriate use of macrolichens as
indicators at this regional scale. First, the presence and high abundance of L. pulmonaria
across most of our research sites (wet or dry) proved not to be a sensitive indicator to
site-specific conditions and lichen diversity (as suggested by Campbell and Fredeen
(2004)). This result concurs with Kalwij et al. (2005) that suggested that L.pulmonaria at
the site level is not sensitive to landscape disturbances, but could be a useful indicator of
lichen diversity and disturbance frequencies when comparing among regional landscapes.
We postulate that within regional landscapes, the presence and abundance of bipartite
cyanolichens would serve as more appropriate indicators of potential biodiversity
"hotspots" (sensu Bergamini et al. 2005), canopy microclimate conditions (Stevenson and
Coxson 2008) and site disturbances (Goward 1994). We must caution, however, that the
proliferation of a guild of bipartite cyanolichen species is a reflection of individual
species' ability to disperse, establish and persist at a particular site. Therefore, while we
may identify that L.retigera and N.occultum are both found in greater numbers and
frequencies in sites of wet BRSM, we must also be aware that co-varying ecological
attributes found in wet BRSM (i.e. soil moisture, temperature, and site disturbance) could
influences the presence of these regionally rare macrolichens differently. Our data
suggests that sites of wet BRSM status are biodiversity hotspots due to a combination of
optimal microclimatic conditions (due to lichen establishment limitations) and potential
stand continuity (due to lichen dispersal limitations).
Radies 16
Glavich et al. (2005) pointed to temperature and moisture as major predictors of
cyanolichen diversity over a vast region of coastal wet temperate rainforests. Our
correlation of environmental attributes with ordination scores suggests that gradients of
temperature and moisture continue to play an important role in shaping cyanolichen
assemblages at finer landscape scales. However, we must stress here, that our climate
variables are derived from climate models (as with Glavich et al. (2005)), not from stand
level measurements. Temperature has long been inferred as an important environmental
variable in structuring ITR cyanolichen communities. Canopy cyanolichens rapidly
diminish in abundance as stand composition shifts from cedar-hemlock to spruce-fir with
increasing elevation (Goward 1994). Studies on cyanolichen physiology suggest that
processes of carbon assimilation and nitrogen fixation are highly rate-limited at low
temperatures (Sundberg et al. 1996). Interactions with precipitation, which can be
viewed as a proxy for the duration of thallus hydration, are also fairly straightforward.
Lichen growth models are highly sensitive to the duration of physiological activity
(Sundberg et al. 1996). Coxson and Stevenson (2007) showed that most growth in L.
pulmonaria populations from the ITR coincides with precipitation events in the spring
and summer (the exception being some snowmelt events in the early spring). Although
thalli are often hydrated for long time periods in the late fall and winter, they are
commonly frozen and experience very low light availability, and hence cannot realize
much growth potential.
The opposing trends in temperature and precipitation with increasing elevation in
ITR mountain valleys would appear to have major constraints on the establishment of
canopy cyanolichens. However, site moisture and relative humidity are not related solely
Radies 17
to precipitation. The amount of slope above a position on the landscape is a major factor
in determining site moisture (Ketcheson et al. 1991). Relative soil moisture status was
significantly correlated with axis 2 of the NMS ordination and was a significant variable
in a majority of best model sets predicted by logistic regression for individual species.
Where wet BRSM status coincides with warmer valley bottom conditions, lichen
communities escape the constraints that would otherwise be placed on their development
by regional gradients of temperature and precipitation. We hypothesize that the greater
relative humidity found within the lower canopy of these stands extends the duration of
periods of metabolic activity experienced by canopy lichens after precipitation events.
This, in combination with the form in which the precipitation falls (i.e., rain versus
snow), would identify more optimal habitat — particularly for cyanolichens, which need
direct contact with water to resume physiological activity (Budel and Lange 1991). This
is evident where one finds adjacent dry BRSM stands with much lower canopy lichen
diversity, notwithstanding very similar exposure to temperature and absolute
precipitation.
Old-forest stands that develop in wet BRSM areas tend to share many common
attributes. Basal areas of cedar, fir, and spruce are greater than in dry BRSM areas,
presumably reflecting the influence of subsurface water on tree growth, and indirectly,
the greater exclusion of fire as a major natural disturbance agent (Eng 2000, Beaty and
Taylor 2001). Importantly, wet stands tended to have a more open canopy structure,
reflecting the greater role of gap dynamics within old-forest stands in water-receiving
positions (Benson and Coxson 2002, Lertzman et al. 2002, Radies and Coxson 2004).
For canopy cyanolichens, this combination of abundant light in a humid lower canopy
Radies 18
environment creates ideal conditions for growth and establishment (Coxson and
Stevenson 2007). Spies and Franklin (1991) postulated that receipt of groundwater flow
and attendant transfer of nutrients was a major determinant of the overall growth,
development and structure of coastal wet temperate rainforests. Spies et al. (2006)
further pointed out the importance of recognizing these site-specific factors when
developing plans for the conservation of old-growth forests. Conversely, higher fire
return intervals on upslope positions, particularity those of south-facing aspects (Eng
2000), have most likely limited the accumulation of rare lichen species — due to both
dispersal limitations (Sillett et al 2000, Hilmo and Sastad 2001) and unfavorable site and
structural characteristics for lichen establishment (as discussed).
Our second major question was whether old-growth lichens, when examined
individually, would select similar environmental variables. The same variables played an
important role in predicting the presence or absence of individual species. All 8 of the
so-called "old-growth associated" lichen species had either temperature or BRSM as
major predictive variables in their best model sets (> 0.1 Akaike's weight), with 6 of
these species having both predictor variables present. However, of the 8 species, only 2
species shared similar parsimonious models and 5 demonstrated varying affinities to
leading old-growth stand type — indicating habitat limitations for some lichen species
across our study area and the importance of stand representation.
Presence of the endangered cyanolichen species N. occultum was predicted best
by wet cedar-leading stands. Evidence suggests that undisturbed wet cedar-leading
stands have persisted for time periods well in excess of the age of the oldest trees,
fulfilling definitions of antique forest stands (Goward and Arsenault 2000). This
Radies 19
suggests that N. occultum is most likely dispersal limited, proliferating only in stands that
reach exceptional ages. Thalli of N. occultum, however, may also be influenced by
greater nutrient availability in water receiving (wet BRSM) stands. These sites receive
groundwater flow from upslope catchment areas, potentially representing a landscape
level transfer of soluble nutrients. Further, on sites where cedar dominates, enrichment of
exchangeable soil calcium can occur through deposition of CaCCb in litterfall (Graff et
al. 1999), a potentially important factor in subsequent enrichment of throughflow
precipitation as it passes over canopy foliage.
Most of the "old-growth associated" lichens that selected for leading species also
demonstrated wide confidence intervals around the respective coefficients. These large
intervals can be explained by the broad autoecological requirements of individual species
themselves and/or the broad scale at which forest stands were measured (in this case,
leading stand type). Importantly, our measurement of "leading-tree species" does not
identify the gradient of mixed conifer forest of cedar, hemlock, spruce and fir most often
found in these forest types. However, the association of lichens within this gradient of
mixed stand types could help explain the similar positive influence of both cedar and
hemlock leading forests on the presence of L. retigera, P.norvegica, and S. oroborealis.
This finding also suggests a broader ecological tolerance to stand conditions by certain
"old-growth associated" lichens, but not by all.
From the perspective of setting priorities for the conservation of canopy lichen
communities, the retention of representative old-forest stands in areas of water-receiving
valley bottom positions should be a high priority for land-use planners. This strategy will
also ensure old-growth ITR landscapes are more resilient by mimicking natural
Radies 20
disturbance regimes (sensu Drever et al. 2006) and protecting regions of temperate
mountain coniferous forests less prone to fire disturbance —such as north-facing aspects
(Eng 2000), moderate slope terrain, and valley bottom locations (Beaty and Taylor 2000).
We also suggest that forest harvesting practices in these regions needs to be more
complex including variable retention single tree and small patch cuts that reflect the
natural range of variability in disturbance events that characterizes these wet old-growth
forest systems (Lertzman et al 2002, Radies and Coxson 2004). Across dry BRSM sites,
particularly those areas more prone to both insect outbreak and fire, clearcut harvesting
may be a more suitable prescription. We emphasize that harvesting strategies must
recognize spatial and temporal scale and pattern discrepancies between wet and dry
BRSM forest types. Ecosystem-based forest management would not "borrow"
disturbance patterns from one moisture type and prescribe it to another (i.e. frequent
clear-cuts in wet BRSM sites).
Current spatial representation of old-forests in protected areas in the ICHvk2 is
approximately 6%, — well below the ecosystem-based threshold target of 53% set for the
upper Fraser River watershed (Anonymous 2004). Given that many of the rare lichens
were only found in one or two wet sites (and not the same ones), it is highly unrealistic to
expect that current protected areas will maintain canopy lichen diversity within regional
landscapes. Furthermore, continued clear-cut forest harvesting in representative wet, low
elevation old-growth forest stands, will likely ensure a greater loss of macrolichen
biodiversity prior to reaching regionally set ecosystem-based old-growth threshold targets
(Anonymous 2004). Indeed, past harvesting of old-forest stands in wet BRSM sites may
Radies 21
already have incurred an "extinction debt" (Berglund and Jonsson 2005) in the upper
Fraser ITR.
CONCLUSION
The application of indicator species requires an understanding of both the natural history
of the organism and the appropriate use of scale and measurement. Our data suggest that
at site-specific scales in mountainous old-growth ITR, bipartite cyanolichens could prove
useful in the determination of areas of high biological value due to both optimal site
conditions (relating to lichen establishment) and potential longevity of the stand itself
(relating to lichen dispersal). Given the reduction in the total area of these site types due
to anthropogenic activities, we recommend that old-forest stands in the upper Fraser
River watershed that have wet BRSM status be given immediate consideration for
protected area status. These sites represent significant biodiversity hotspots for canopy
lichens that are essential for the maintenance of biodiversity within larger regional
landscapes. The distribution of these organisms highlights the importance of
appropriately identifying soil moisture site discrepancies in old-growth forests for the
purposes of executing effective ecosystem-based management thresholds and strategies.
Therefore, when applying old-growth thresholds to temperate old-growth rainforests, the
question, "how much is really enough?" (Price et al. 2008), must also be coupled with,
"of what kind, in what location, and in what context?". Otherwise, the objective of
setting threshold targets for the purposes of maintaining biodiversity will most likely miss
its mark.
Radies 22
CHAPTER 2: PARALLELS BETWEEN OLD-GROWTH FOREST RETENTION
TARGETS AND THE CHILDREN'S GAME KERPLUNK!
INTRODUCTION
Remember the children's game "KerPlunk!"? For those who have forgotten, or were
never exposed, the game was very simple. Players first created a crisscross horizontal
web of tiny plastic colored sticks strategically placed through holes about the centre
region of a vertically standing plastic tube. Marbles were then added to the top of the
tube, in which the sticks in the center of the tube immediately halted their downward
momentum. At this point, the game begins. Players remove the sticks, and "with a bit of
skill and a little luck, you can keep a lot of marbles from going KerPlunk!" With this in
mind, let's draw some comparisons between this game and maintaining biodiversity and
ecological integrity using old-growth retention targets in B.C.'s Inland Temperate
Rainforests.
The purpose of setting old-growth retention targets is to maintain ecological
integrity and biodiversity associated with these older forests (Anonymous 2004, Price et
al. 2008). In some areas, determining these threshold targets are based on the
determination of the Natural Range of Variability (NRV) — a set amount of old-growth
found within an ecological unit. The assumption in NRV theory is that biological
diversity will be impacted less if forest management follows similar temporal and spatial
patterns of natural disturbances (sensu Drever et al. 2007). However, identifying
appropriate scale (both temporally and spatially) is critical for the effectiveness of such a
management system (Grumbine 1994, Drever et al. 2007).
Radies 23
In British Columbia, when old-growth threshold targets are applied, they are most
often set at the biogeoclimatic subzone scale for forests greater than 140 years (Wells et
al. 2003, Anonymous 2004, Coast Information Team 2004). Assuming these to be
appropriate spatial and temporal units of scale, the question: "how much [old-growth] is
really enough?" (Price et al. 2008), to maintain biodiversity is the next logical question in
forest management; in other words, how far can we push old-growth threshold targets
without ecological consequences? Although this may sound like a seemingly easy
question, it is not. However, the province is accepting a "low risk to biodiversity" if an
old-growth threshold target of 70% the minimum NRV is implemented in forests greater
than 140 years at the biogeoclimatic subzone unit in wet mountain forests (Wells et al.
2003, Anonymous 2004). An example of this old-growth management strategy can be
found in the Prince George Timber Supply Area (PGTSA) (Anonymous 2004).
In the PGTSA, most ecological input for setting old-growth threshold targets
followed two scientific works: 1. DeLong's (2007) estimation of the Natural Range of
Variability (NRV) in the Prince George Forest region and; 2. DeLong et al. (2004) work
comparing wildlife tree habitat value between mature (class 8, 140-250 years of age) and
old (class 9, 250 years or older) forests. The NRV study results identified a NRV for
forest >140 years within the inland rainforest (called Wet Trench-Valley) at 76-84%
(DeLong 2007). The second study by Delong et al. (2004) found that wildlife tree habitat
measurements did not seem to discriminate between age class 8 and 9 stands (thus
allowing the incorporation of class 8 stands to fulfill old-growth threshold requirements).
Given these results — in combination with the accepted setting of old-growth thresholds
at 70% the minimum NRV — a 53% non-spatial old-growth threshold target for Wet
Radies 24
Trench-Valley forests over 140 years of age was accepted into regional policy
(Anonymous 2004, Delong 2007). In other words, the only requirement for meeting the
53% old-growth retention target is that forests are 140 years of age. Thus, old-growth
threshold targets can be non-spatially met primarily in the Non Timber Harvesting
Landbase (NHLB) that constitutes approximately half of the remaining old-growth forest
landbase in the PGTSA (Anonymous 2005). But will this old-growth threshold approach
be capable of maintaining biodiversity?
One group of organisms that has been of considerable concern in ITR ecosystems is
canopy lichens (Goward and Arsenault 2000, Goward and Spribille 2005). Arboreal
lichens have been shown at the site level to be influenced by both age (Campbell and
Fredeen 2004, Radies and Coxson 2004) and stand characteristics (Goward and Arsenault
2003, Coxson and Stevenson 2007, Stevenson and Coxson 2008). Therefore, arboreal
macrolichens seem to be an appropriate group of organisms with witch to test the
effectiveness of an aspatial old-growth theshold policy in ITR forests. To do this, I
compared the presence or absence of 37 macrolichen species in forests greater than 140
years of age by two broad-scale ecological variables — leading tree species and broad
soil moisture regime status. My reasoning for choosing these two main variables was: 1.
they both greatly influence the NRV (i.e. fire return, insect outbreak), stand structure and
tree composition in mountain forests (Spies and Franklin 1991, Eng 2000, Beaty and
Taylor 2001) and; 2. they are both practical in landscape-level queries, such as building
species predictability maps, using provincial GIS tools (most notably, the Vegetation
Resource Inventory (VRI) (Anonymous 1998) for leading tree species and the Predictive
Ecosystem Mapping (PEM) (Anonymous 1999) database for soil moisture regime). The
Radies 25
questions I therefore explored using these two central forest variables in combination
with presence/absence macrolichen data were as follows:
•
Do canopy macrolichens significantly vary in their presence between old-growth
forests greater than 140 years of age in wet soil moisture conditions versus dry
relative soil moisture conditions
•
What percentage of the ICHvk2 old-gorwth forest is in wet and dry relative soil
moisture conditions and of this, what proportion is inside or outside the timber
harvesting landbase?
•
Can we manage old-growth forests for biodiversity and ecological integrity using
threshold targets set at the biogeoclimatic unit scale?
•
Can we make any inferences from our lichen results that would suggest that areas
outside or inside the THLB are more susceptible to natural disturbances?
•
Can we use VRI and PEM to build meaningful coarse filter predictability maps
for canopy lichens of concern?
It is my hope that the overall findings in this report will provide useful information
for forest managers in BC on the benefits and pitfalls of old-growth threshold targets set
at the biogeoclimatic unit scale.
METHODS
Study area
The study area is located in one of two variants of the very wet Interior Cedar
Hemlock Biogeoclimatic SubZone — The ICHvk2 of the upper Fraser River watershed
(Fig. 2-1). ICHvk systems are the wettest low elevation cedar-leading forests in the
interior of the province and are found in only two locations, one in the south near
Radies 26
Revelstoke (the ICHvkl) and the other near Prince George (the ICHvk2) (Fig. 2-1).
These vk systems are located in the northern portion of the Inland Temperate Rainforest
(ITR) bioregion (Inset Fig. 2-1) and are part of the ICH "wet-belt" region (ICH wet and
very wet subzones) (Fig. 2-1). The ICH wet-belt and its surrounding watersheds have
had extensive clearcut logging in the past 50 years (Fig. 2-2). The majority of remaining
class 8 (140-250 years) and class 9 (250 years or older) ICH wet-belt forests are restricted
and most extensive in the northern ITR region, (Fig. 2-3), in which provincial park
protection of ICHvkl and vk2 old-growth forests (Fig. 2-2) is spatially minimal (Fig. 23). Figure 2-4 identifies the extent of clear-cut forest harvesting in and around the
ICHvk2 and lower elevation very wet Sub Boreal Spruce (SBSvk) biogeoclimatic
subzone of the upper Fraser River watershed (note that the area that appears to have no
cutblocks is TFL 30 for which the information was not available at time of writing).
Figure 2-5 outlines study area and plot locations in the SBSvk and ICHvk2 (divided into
the vk2 and wk4 during time of study (see Inset Fig. 2-6)) and Figure 2-6 identifies the
varying distribution of cedar {Thuja plicata), hemlock (Tsuga heterophylla), spruce
(Picea glauca x engelmannii), and "other" coniferous leading forests greater than 140
years of age in the ICHvk2 and ICHwk4 (using the VRI).
Minimum and maximum climate data for the 53 study sites (from Chapter 1) were
as follows: Absolute precipitation, 736mm-917mm; Average minimum temperature, 3.14°C to -1.65°C; Average maximum temperature, 7.96°C to 9.92°C; Mean annual
average temperature: 2.44°C to 4.03°C; Average 8 month physiological temp range:
0.553°C to 2.39°C.
Radies 27
Study design
Research plots were established in 53 randomly stratified mature and old-growth
forest polygons in the SBSvk and ICHvk2 (now divided into the ICHvk2 and ICHwk4).
My primary sampling objective was to collect from an equal number cedar, hemlock, or
spruce-leading old-growth forests (greater than 140 years of age) in both wet and dry
Broad Soil Moisture Regime (BSMR) sites. At each stand, we laid out 2 plots that shared
a common centre (Fig. 2-7). The lichen assessment plot was a rectangular survey area
40m x 100m, with the long axis parallel with the slope contours to avoid marked
topographic changes. Each plot was assessed for 37 possible arboreal foliose lichens
(checklist adapted from Go ward et al. 1994, see Table 2-1 for list of species and
abbreviations) using survey methods of McCune et al. (2000). Melanelia and Parmelia
lichens were surveyed at the genus level. The stand structure plot was a circular plot with
a radius of 17.8 m for the purpose of measuring stand structure and relative soil moisture
conditions. We used densiometer measurements at 13 locations in each lichen
assessment plot to obtain the overall "openness" of the stand.
Predicted mean annual precipitation and temperature for each stand was obtained
from the Canadian Forest Service (CFS) regional climate database (Hutchinson 1995).
We used mean monthly minimum temperature for the months March-October in our
analysis; this reflected the seasonal time period during which most lichen growth occurs
(Coxson and Stevenson 2007). Potential solar insolation was calculated using SAGAGIS Version 2.0 (Scilands GmbH, Gottingen, Germany) solar radiation model.
To analyze data for the purposes of fitting field data to PEM and VRI data, we
categorized both site and stand variables. Sites were classified as wet BSMR when the
Radies 28
soil moisture regime was above 4 on the 7-point soil moisture scale, and dry BSMR if the
soil moisture regime was less than 4 (corresponding to mesic or submesic sites in
DeLong's (2003) soil moisture regime key). When stands were classified as a 4 (mesic),
vegetation and soil characteristics were used to separate wet versus dry BSMR categories
(i.e. mesic wet versus mesic dry site conditions). Leading tree species (LEAD) was
categorized as stands leading in cedar (Cw), hemlock (Hw), or spruce (Sx), based on the
tree species that had the highest Basal Area in the stand (to be consistent with VRJ
classification methodology). For analysis of "rareness" to "commonness" of species
present in sites surveyed, a presence/absence dendrogram analysis for species was
applied for all sample locations (by BRSM site category) following methods in McCune
and Mefford (1999) (PC-ORD V. 4.0).
We used beta coefficients derived from logistic regression results from Chapter 1
to map, using VRI and PEM, important environmental factors that influenced the
distribution of 3 of 8 old-growth associated lichens — Cavernularia hultenii, Lobaria
retigera, and Nephroma occultum. Independent variables used in Chapter 1 to assess for
each lichen species included: BRSM (categorical), canopy openness (OPEN), average
minimum temperature (TEMP), average annual precipitation (PRECIP), solar insolation
(SOLAR), and LEAD (categorical) (see Table 2-2). We tested thirteen combinations of
independent variables that served as plausible explanatory hypotheses for the distribution
of each of the 3 lichen species (Table 3-3). We used Akaike's Information Criterion with
a correction for small sample size (AICC) (Johnson and Omland 2004) to identify the
most parsimonious logistic regression model. We calculated the area under the Receiver
Operating Characteristic (ROC) curve for the top-ranked models (Munoz and Felicisimo
Radies 29
2004). ROC scores allowed us to evaluate the ability of the most parsimonious model to
predict the distribution of lichens on the landscape. We used Multi-Model Inference
(MMI) to determine the relative importance of the predictor variables for each species
(Johnson and Omland 2004). We used 95% confidence intervals, corrected for model
selection uncertainty, to assess the strength of effect of each predictor covariate on the
dependent variable. To map the probability of occurrence for L .retigera, N. occultum,
and Cavernularia hultennii across the study area we combined beta coefficient values
(from Chapter 1) to VRI, PEM, and climate data. Probabilities for each cell were
calculated according to eqn 1 and represented the sum of each beta coefficient multiplied
by the respective GIS value. Eq. 1. y = PiX] + P2X2... -PNXN- Relative to eqn 1, the p is
the average MMI coefficient (i.e. for BSMR, LEAD, SOLAR), and X is derived from the
GIS databases from PEM (for BSMR), VRI (for LEAD and OPEN), CFS climate data
(for TEMP and PRECIP), and solar insolance (for SOLAR).
BSMR site conditions were determined from queries in PEM. We assigned
polygons with a dominant (41-100%) site series of mesic, subhygric, or hygric to a wet
BSMR status, and polygons with a submesic, subxeric or xeric dominant site series (41100%) to a dry BSMR status. Polygons with a primary mesic site series between 41 to
90% combined with a secondary (10-49%) submesic site series, were classified as having
a dry SMR status. This analysis was combined with forest inventory data to estimate the
remaining area of old-forest in the ICHvk2 by age class (140-250 years old or > 250
years old), leading tree species (spruce, hemlock and cedar), and BSMR status (wet or
dry) inside the Timber Harvesting Landbase (THLB) and outside the THLB (NHLB)
(including parks and Old Growth Management Areas).
Radies 30
RESULTS
Sites were relatively evenly distributed between BSMR and LEAD categories
(Table 2-4). Based on the presence/absence dendrogram for all species measured, we
found trends that identify similarity of both site and macrolichen species (Fig. 2-8). The
species axis categorized 3 major subgroups, in which (from left to right) macrolichens are
"rare" (found in less than 50% of the sites), "less common" (found in more than 50% of
the sites), or "common" (found present in almost all sites). On the site axis, we see a
division into 2 major subgroups, in which (from top to bottom) dry sites dominate (18 of
26) in the first subgroup and wet BSMR sites dominate in the second subgroup (19 of 25
times). Overall, wet BSMR subgroups had higher levels of macrolichen diversity,
particularly for the bipartite cyanolichen species.
PEM and VRI derived data compared well with field-derived variables, with the
exception of canopy openness, for which accuracy from the VRI database was
inconsistent (<25% accurate), forcing us to construct maps of lichen distribution without
this variable. Leading species field data was found to be 77% accurate when compared
with the VRI database and BSMR categorization was 74% accurate within the PEM
database (following outlined definitions of wet and dry BSMR polygons). The resulting
maps illustrate the distribution of wet (mesic wet to subhygric) and dry (mesic dry to
xeric) BSMR old-growth sites (Fig. 2-9) and our selected lichen species (Fig. 2-10, 2-11,
and 2-12). Spatial predictions placed L. retigera predominantly in areas with warmer
temperatures and in hemlock- or cedar- leading stands (Fig. 2-11). C. hultennii (Fig. 210) and N. occultum (Fig. 2-12), both predicted by the model BSMR X LEAD, illustrate
the usefulness of leading tree species (VRI data) combined with BSMR (PEM data) to
Radies 31
create predictive landscape maps. However, although our ROC scores indicated a good
predictability when applying these models to PEM and VRI, it is beyond the scope of this
paper to fully analyze the accuracy of the PEM and VRI databases.
From the forest inventory data (as of 2006), 64.3% (67,769 ha) of the total
forested area of the ICHvk2 biogeoclimatic zone is composed of cedar-, hemlock-, and
spruce-leading stands > 140 years old (Table 2-5). Of this area, representation is near
equal between wet and dry sites (29% and 35% respectively). Total protection is also
relatively similar between wet and dry BSMR sites at approximately 6% each. However,
areas identified as not in the Timber Harvesting Landbase (NHLB) differed between wet
and dry BSMR conditions, in which 11.3% (39.7% of 29) wet BSMR sites and 19.3%
(54.7% of 35.3) dry BSMR old-growth sites are found in the NHLB.
DISCUSSION
Dendrogram results identified that canopy macrolichens are not equally present in mid to
low elevation coniferous mountain forests greater than 140 years of age in the upper
Fraser River watershed. Notably, wet soil moisture sites (mesic wet and wetter),
contained a greater number of rare and uncommon canopy lichen occurrences than those
dry soil moisture sites (mesic dry or drier). This result is somewhat intuitive, as moisture
has been shown to play a critical role in the distribution of lichen species near streams
(Liden and Hilmo 2005) and in temperate regions of increasing precipitation (Goward
and Spribille 2005). However, understanding the influence ground moisture plays on the
presence of canopy cyanolichens is not well understood.
In Chapter 1, Radies et al. hypothesized that increasing soil moisture would
increase air humidity, allowing for the establishment and proliferation of a lichen species
Radies 32
restricted by the requirement of longer periods of thallus hydration. However, Radies et
al. (Chapter 1) also recognized a combination of other ecological characteristics in sites
of wet soil moisture that co-vary and likely influence the presence or absence of rare
canopy lichens, namely: 1. a difference in canopy structure that favors the establishment
of cyanolichen species, such as a more open canopy structure that allows for an increase
in direct thallus wetting episodes, lighting periods, and substrate availability; 2. higher
temperatures, due to lower topographic positioning, and; 3. an increase in site continuity
due to the absence of natural disturbances (i.e. stand destroying fires) on topographically
wet sites, augmenting the probability of rare lichen species occurrences. Notable here, is
that the first two points assume forests after reaching 140 years of age will contain an
equal opportunity to house rare species if structural and microclimatic conditions remain
constant. Our species predictability maps are based on this assumption (following
current NRV forest policy), delineating the probability of species occurrence based on
microclimate and stand-level characteristics. But why then, are rare species absent in
regions delineated suitable in our habitat models? For example, if we consider the
predictability map of the threatened species Nephroma occultum, we see that it has a
higher probability of selecting for wet cedar-leading forests in the ICHvk2. Is this
selection for wet cedar leading forests (that are believed exceptional in age) a result of a
species limited by establishment or dispersal?
Although there is evidence that favorable lichen establishment environments in
old-growth forests constitutes a critical phase in the proliferation of arboreal lichens
(Hilmo and Sastad, 2001), successful transplant experiments in younger forest stands
suggests that for some lichens, dispersal is a limitation (Rosso et al. 2000; Sillet et al.
Radies 33
2000). This is a critical point; as dispersal limitation highlights the critical role temporal
scale plays in the landscape distribution of rare epiphytic species. In this case, similar
site and structural characteristics will not be as important to species as forests that are
extremely old (as the probability of species presence, limited by dispersal, increases with
time). This emphasizes the importance of temporal scale in NRV management that is
vital to biological diversity. Therefore, to improve NRV forest management in British
Columbia, we must readdress how we intend to identify, describe and manage old-growth
forests after they reach 140 years of age.
Managing for natural disturbances at the biogeoclimatic subzone scale: doing our best
given what we know
It is well known that fire is distributed unequally across mountain landscapes
(Spies et al. 2006). This distribution of fire frequency and intensity is most often
correlated with wet or dry forest stand conditions at multiple scales (Eng 2000, Beaty and
Taylor 2001). This is why we recognize, at a broad scale, that ITR forests burn more
frequently than coastal rainforests — as ITR receives approximately half the annual
precipitation as its coastal counterpart. At finer scales, spatial patterns of fire emerge as a
result of aspect, slope and soil characteristics in mountainous forests (Beaty and Taylor
2001). For example, while studying drier mountain forests near our study area in the
upper Fraser River watershed Eng (2000) noted an almost 10-fold increase in fire
intensity on south facing slopes. This pattern of dry and wet site conditions clearly
emerges when we review Insets 2 and 3 from Figure 1-1 showing south-facing slopes of
Driscoll Ridge dominated by dry BSMR sites (mostly mesic dry and submesic sites) and
north-facing slopes of the ridge dominated by wet BSMR sites (mostly mesic wet and
Radies 34
subhygric conditions) in the ICHvk2 and SBSvk. This query demonstrates the usefulness
of PEM when developing and implementing NRV in old-growth forest landscapes, which
can identify forested regions that are potentially more prone to fire disturbance.
If we compare forest stands inside and outside the timber harvesting landbase
(THLB) (Table 2-5), we find a higher amount of wet BSMR sites potentially available for
future harvesting throughout all forest stand types. The potential result of this timber
supply model would be a forested landscape where remaining old-growth stands were
more susceptible to fire disturbance (as there would be more water shedding old-growth
forest on the landscape). This demonstrates how aspatial objectives for setting oldgrowth threshold targets can run counter to NRV forest policy objectives set by the BC
Ministry of the Environment for the purpose of maintaining species diversity
(Anonymous 2004). In other words, if NRV forest policies do not recognize the
implications of aspatial old forest targets, which do not require representation of forests
in wet BSMR conditions, how is it possible to maintain ecological integrity in these oldgrowth forest systems (sensu Drever et al. 2006)? For example, given current NRV
policy in the PGTSA it is possible to harvest 10% of the remaining forest which could
potentially remove all remaining class 9 cedar-leading stands (outside protected area)
regardless of their spatial or temporal distribution within a biogeoclimatic subzone (Table
2-5). Furthermore, the reduction of the NRV old-growth management thresholds from a
predicted "natural" baseline of approximately 80% to 53%, due to timber supply
concerns, highlights why it is critical to maintain stand and site conditions that are
optimal to maintain lichen species richness in the upper Fraser River watershed.
Radies 35
One approach that could address these stand and site level concerns is to include
both spatial and temporal forest stand representation in old-growth management policy at
the biogeoclimatic subzone scale. This means that forests would need to be
proportionally represented on the landscape both spatially (i.e. based on tree species
composition and site condition) and temporally (i.e. higher or lower old-growth threshold
targets based on NRV). The result of this approach would be an old-growth forest
landscape equally represented in proportions more reflective of a natural landscape (to
the best of our understanding). Notable here, is that the increasingly popular application
(provincially) of identifying ecological risk by representing site series by equal area (for
example see Ecosystem Representation in TFL 30) does not align well with most NRV or
Ecosystem-based Management (EBM) literature (sensu Grumbine 1994, Drever et al.
2006). The criticism here is that the site series within an biogeoclimatic subzone will not
be represented by the natural spatial and temporal distribution found within the ecological
unit.
SUMMARY
Temperate inland mountain old-growth forests of BC are complex at regional scales;
ranging from younger dry hemlock dominated forest on topographically dry ridges to
older wet cedar dominated forests in water receiving areas. Recognizing these spatial and
temporal landscape patterns are a first step to improving both NRV and/or EBM goals
and objectives for maintaining biodiversity and ecosystem integrity in BC. The results of
this study concur with NRV theory by identifying an increase in the presence of rare and
uncommon canopy macrolichens in water receiving regions of the landscape that are
more than likely less disturbed by natural disturbances such as fire. We therefore
Radies 36
recommend that NRV policy address appropriate spatial and temporal representation of
old-growth forest stands within biogeoclimatic subzones. To compare these old-growth
threshold targets to the game Kerplunk!, we recognize that the removal of each tree, or
hectare of forest, is not always equal for the purpose of maintaining biological diversity;
likewise, removing a given number of sticks from a Kerplunk! tube for the purpose of
preventing marbles from dropping does not always have equal results.
Recommendations for implementing EBMfor the purpose of maintaining biodiversity
and ecological integrity in old-growth inland temperate rainforests.
1. Recognize and identify in policy, given the best of current knowledge, the
temporal and spatial distribution of natural disturbances in forests at the
biogeoclimatic subzone scale. Importantly, recognize the role class 9 forests
(identified as greater than 250 years) play in the distribution of species known or
believed limited by dispersal.
2. Update provincial databases to identify previous stand composition and structure
in previously harvested old-growth sites. For example, wet cedar-leading forests,
multi-aged, with a secondary layer of hybrid spruce.
3. Recognize that although human activity is part of NRV and/or EBM forest
management, we must first construct (to the best of our ability) how stand
Radies 37
processes would have occurred across the landscape without human intervention.
This becomes an essential baseline layer in which to measure human impacts.
4. Measure other taxonomic groups other than lichens to determine if they are also
following similar ecological patterns.
5. Focus future research to address knowledge gaps in above recommendations.
CONCLUSION
The purpose of this thesis was to ask if macrolichen species differed across a
regional old-growth landscape, and if so, what ecological characteristics emerge to
influence this distribution. From our results we identify that for some groups, such as the
chlorolichens, the distribution is relatively equal, while for others, such as the
cyanolichens, the distribution in old-growth forested landscapes is distinctly unequal,
concentrating in lower elevation water-receiving slope positions. Reasons or hypotheses
for this concentration of uncommon and rare species occurrences in these regions are
numerous (some of which are identified in this thesis), yet still not entirely known.
However, it is unlikely that a "one shoe fits all" hypothesis will unravel this cryptic
ecological message, in which we find species of the same guild selecting for differing
stand variables within water receiving slope positions. As with most scientific inquiries,
more questions than answers have emerged.
From the perspective of managing (i.e. doing forestry) in these old-growth forests,
consideration of this study must be put into context. First, we must remember that this
Radies 38
landscape study measured 37 species out of a total that is well into the thousands, and
that many taxonomists other than lichenologists have yet to set foot in this forested
system. For this reason alone, the size of refuge needed for the conservation of
biodiversity in these inland old-growth temperate rainforests is nothing short of a well
informed guess. Therefore, it is best that we err on the side of caution and recommend
that old-growth forest in water receiving positions be conserved (and appropriately
represented by stand composition and structure) until further scientific research indicates
otherwise.
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Portland, Oregon General Technical Report PNW-GTR-285.
Spies, T.A, M.A. Hemstrom, A. Youngblood, and S. Hummel. 2006. Conserving oldgrowth forest diversity in disturbance-prone landscapes. Conservation Biology
20:351-362.
Stevenson, S.K., H.M. Armleder, M.J. Ml, D.G. King, B.N. McLellan, and D.S. Coxson.
2001. Mountain caribou in managed forests: recommendations for managers:
Second Edition. B.C. Min. Environ., Lands, and Parks. Wildlife Rep. No. R-26.
Victoria, B.C.
Stevenson, S.K., and D.S. Coxson. 2008. Edge effects on Lobaria retigera in B.C.'s
inland temperate rainforest. Forest Ecology and Management (in-submission).
Sundberg, B., K. Palmqvist, P.A. Esseen, and K.E. Renhorn. 1996. Growth and vitality
ofepiphytic lichens. II. Modelling of carbon gain using field and laboratory data .
Oecologia 109:10-18.
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Review of Ecology and Systematics 20:171-197.
Walker, B.H. 1992. Biodiversity and ecological redundancy. Conservation Biology
6:18-23.
Radies 47
Wells, R.W., Bunnell, F.L., D. Haag, and G. Sutherland. 2003. Evaluating ecological
representation within differing planning objectives for the central coast of British
Columbia. Canadian Journal of Forest Research. 33: 2141-2150.
Zinko, U., Seibert, J., Dynesius, M., and C. Nilsson, C. 2005. Plant species numbers
predicted by a topography-based groundwater flow index. Ecosystems 8:430441.
Radies 48
TABLES
Table 1-1.
Species
Dry Stand Plots
Wet Stand Plots
(27 sites total)
(26 sites total)
Number of site occurrences and occurrences by
abundance scale: very low (VL), low (L), common
(C)
CHLOROLICHENS
# of dry sites (VL, L,C)
Cavernularia hultenii
7 (5,2,0)
14 (7,3,4)
Cetraria cetroides
0
1 (1,0,0)
Hypogymnia austerodes
2 (2,0,0)
1 (1,0,0)
H. bitteri
18(3,7,8)
17 (2,6,9)
H Jmshaugii
0
1 (1,0,0)
H. metaphysodes
19(4,4,11)
14 (7,3,4)
H .occidentalis
26(0,1,25)
26 (0,0,26)
H .oroborealis
3 (3,0,0)
2 (2,0,0)
H. physodes
27 (0,0,27)
26 (0,0,26)
H. rugosa
19(4,11,4)
20(4,10,6)
H. tubulosa
27 (0,4,23)
26 (0,2,24)
H. vittata
23 (4,9,10)
25 (0,4,21)
Melanelia spp.
15(11,3,1)
15(7,7,1)
Parmelia spp.
27 (0,0,27)
26 (0,0,26)
Parmeliopsis ambigua
26(3,11,12)
26(1,9,16)
Radies 49
# of wet sites (VL, L, C)
P. hyperopta
27 (2,6,19)
26(1,4,21)
Platismatia glauca
27 (0,0,27)
26 (0,0,26)
P. norvegica
18(5,8,5)
17(5,7,5)
Tuckermannopsis chlorophylla
27(1,9,17)
26(2,1,23)
T. orbata
7(3,3,1)
2 (2,0,0)
Vulpicida pinastri
12 (6,4,2)
14(7,4,3)
CYANOLICHENS
# of dry sites (VL,L,C)
# of wet sites (VL,L,C)
Leptogium burnetiae
0
1 (1,0,0)
L. saturninum
2(1,0,1)
4 (2,0,2)
Lobaria hallii
0
3 (3,0,0)
Lobaria pulmonaria *
27(1,1,25)
26 (0,0,26)
Lobaria retigera
2 (2,0,0)
12 (6,2,4)
Lobaria scrobiculata
19(9,7,3)
23(1,10,11)
Nephroma bellum
11(4,5,2)
18(7,7,4)
Nephroma helveticum
23 (4,6,13)
26 (0,3,23)
Nephroma isidiosum
11(4,6,1)
23 (6,5,12)
Nephroma occultum
3 (3,0,0)
11(10,1,0)
Nephroma parile
24(4,7,13)
26 (0,3,23)
Nephroma resupinatum
1 (0,1,0)
1 (0,0,1)
Peltigera collina
1 (0,1,0)
5 (3,1,0)
Polychidium dendriscum
0
7 (2,3,2)
Pseudocypellaria anomala
19 (8,8,3)
26(3,6,17)
Sticta fuliginosa
17(10,4,3)
23 (2,4,17)
Radies 50
Sticta limbata
0
2 (2,0,0)
Sticta oroborealis
3 (1,2,3)
12 (5,4,3)
Sticta wrightii
2 (2,0,0)
1 (1,0,0)
Radies 51
Table 1-2.
Variable
Coefficient
SE
t
P
CONSTANT
40.199
18.270
2.200
0.033
Temperature
-6.139
1.726
-3.557
< 0.001
Precipitation
-13.848
5.751
-2.408
0.021
Solar Loading
1.240
0.751
1.652
0.106
Basal Area (Hw)
0.180
0.127
1.420
0.163
Basal Area (Cw)
0.110
0.101
1.089
0.283
Basal Area (Sx)
-0.146
0.137
-1.068
0.292
Basal Area (Sf)
0.209
0.199
1.049
0.301
Relative Soil Moisture
-0.806
0.943
-0.855
0.398
Canopy Openness
-0.301
0.479
-0.628
0.534
-61.304
22.412
-2.733
0.009
Relative Soil Moisture
3.760
1.158
3.247
0.002
Temperature
6.139
2.118
3.002
0.005
Canopy Openness
1.58
0.588
2.689
0.01
Precipitation
17.019
7.060
2.411
0.02
Basal Area (Sx)
-0.383
0.168
-2.280
0.028
Basal Area (Hw)
0.263
0.155
1.694
0.098
Solar Loading
1.429
0.992
1.551
0.129
Basal Area (Sf)
0.322
0.245
1.317
0.195
AXIS1
AXIS 2
CONSTANT
Radies 52
Basal Area (Cw)
0.115
0.124
Radies 53
0.928
0.359
Table 1-3.
Stand
Stand Variables
Type
Mean
Minimum
Annual
Solar Loading
% Canopy
Temperature
Mar.-Oct.
Precipitation
(kWh/m2)1
Openness2
(°C) '
Temperature
(mm)
TO1Mean
SD
Mean
SD
Mean
SD
Mean
SD
Mean
SD
DRY
3~1
04
LI
04
831.3
4L2
1208.7 238.0
8^6
~2X
WET
3.5
0.4
1.8
0.3
811.5
32.9
1218.0 108.2
14.1
6.3
Stand
Stand Variables
Type
Stand Basal
Basal Area
Basal Area-
Basal Area-
Basal Area-
Area
Fir
Cedar
Hemlock
Spruce
(m 2 /ha) 2
(m2/ha)2-
(m 2 /ha) 2 '
(m 2 /ha) 2
(m 2 /ha) z
Mean
SD
Mean
SD
Mean
SD
Mean
sT3
Mean
SD~
DRY
76.6
27/7
23
2^8
348
4L0
16l
1A9
8^4^
9^
WET
80.2
48.8
4.0
4.9
43.1
64.9
13.7
21.3
11.0
11.5
Radies 54
Table 1-4.
Species
Best Model Sets (>0.1 AICcw)
AICcw
ROC
Cavernularia hultenii
LEAD (Hw) X BRSM (wet)
0.972
0.856
Lobaria retigera
LEAD (Hw) X OPEN X TEMP
0.607
0.914
Nephroma isidiosum
BRSM (wet) X OPEN X TEMP X PRECIP
0.419
0.918
Nephroma occultum
LEAD (Cw) X BRSM (wet)
0.881
0.815
Platismatia norvegica
LEAD (Hw) X TEMP
0.525
0.718
Peltigera collina
BRSM (wet) X TEMP
0.333
0.737
Sticta fuliginosa
OPEN X TEMP
0.458
0.850
Sticta oroborealis
LEAD (Hw) X OPEN X TEMP
0.956
0.956
Radies 55
Table 2-1.
Species
Abbreviation
CHLOROLICHENS
Cavernularia hultenii
CAVEHULT
Cetraria cetroides
CETRCETR
Hypogymnia austerodes
HYPOAUST
H. bitteri
HYPOBITT
H .imshaugii
HYPOIMSH
H. metaphysodes
HYPOMETA
H .occidentalis
HYPOOCCI
H .oroborealis
HYPOOROB
H. physodes
HYPOPHYS
H. rugosa
HYPORUGO
H. tubulosa
HYPOTUBU
H. vittata
HYPOVITT
Melanelia spp.
MELASPP.
Parmelia spp.
PARMSPP.
Parmeliopsis ambigua
PARMAMBI
P. hyperopta
PARMHYPER
Platismatia glauca
PLATGLAU
P. norvegica
PLATNORV
Radies 56
Tuckermannopsis chlorophylla
TUCKCHLO
T. orbata
TUCKORBA
Vulpicida pinastri
VULPPINA
CYANOLICHENS
Leptogium burnetiae
LEPTBURN
L. saturninum
LEPTSATU
Lobaria hallii
LOBAHALL
Lobaria pulmonaria
LOBAPULM
Lobaria retigera
LOBARETI
Lobaria scrobiculata
LOBASCRO
Nephroma bellum
NEPHBELL
Nephroma helveticum
NEPHHELV
Nephroma isidiosum
NEPHISID
Nephroma occultum
NEPHOCCU
Nephroma parile
NEPHPARI
Nephroma resupinatum
NEPHRESU
Peltigera collina
PELTCOLL
Polychidium dendriscum
POLYDEND
Pseudocypellaria anomala
PSEUANOM
Sticta fuliginosa
STICFULI
Sticta limbata
STICLIMB
Sticta oroborealis
STICOROB
Sticta wrightii
STICWRIG
Radies 57
Table 2-2.
Variable
Description
BSMR
Broad Soil Moisture Regime measured as Dry (0) or Wet (1)
OPEN
Average densiometer measurements in lichen plot
TEMP
Average minimum temperature between March to October
PRECIP
Average (absolute) annual precipitation
SOLAR
Measure of solar insolence, based on aspect, topography, and elev
LEAD
Leading tree species. Cw (0), Hw (1), Sx (2)
Radies 58
Table 2-3.
1. BSMR (2) X OPEN X TEMP X PRECIP
E. BSMR (2) X OPEN X TEMP X SOLAR
3. BSMR (2) X PRECIP
4. BSMR (2) X TEMP
5. LEAD (3) X BSMR (2)
6. LEAD (3) X OPEN X TEMP
7. LEAD (3) X OPEN X PRECIP
8. LEAD (3) X OPEN X SOLAR
9. LEAD (3) X PRECIP
10. LEAD (3) X TEMP
11. OPEN X PRECIP X SOLAR X TEMP
12. OPEN X PRECIP
13. OPEN X TEMP
Radies 59
Table 2-4.
DRY SMR
WET SMR
Cedar
11
11
Hemlock
10
6
Spruce
6
11
27 sites
26 sites
Radies 60
Table 2-5.
DrySMR
Leading
Wet SMR
Tree
Stand
% Total
% Protection
% Total
% Protection
Species
Age
(% NHLB)
(Park, OGMA)
(%NHLB)
(Park, OGMA)
Cedar
140-250
8.5(51)
0.81 (0.41,0.4)
5.9(27)
0.65(0.53,0.12)
250+
5.8 (64)
1.19(0.31,0.88)
7.1(38)
1.44(0.27,1.17)
Hemlock
140+
4.25 (59)
1.1(0.4,0.7)
1.6(44)
0.9(0.7,0.2)
Spruce
140+
13.2 (50)
2.0(1.5,0.5)
12.7(45)
2.62(2.1,0.5)
Other
140 +
3.5 (63)
0.65(0.5,0.15)
1.7(47)
0.32(0.3,0.02)
35.3 (54.7)
5.8(3.1,2.7)
29 (39.7)
5.9 (3.9, 2.0)
Total
Radies 61
Figure 1-1.
•-Zf-i."*. •!
^ • ^ ^ xv
' **" a>n-ccdll Riclse
?%•? J%''
'*%
..
,
%,
Insert .V Dnscoll Ridge - Souili Slope
LEGEND
• B F a r l y Scroll <40ye.irsl
Cudui. Di\
• H Ccxhii, Wet
, Hemlock. Drv
M I tan toe k. Wei
Spruce. Dry
• • Spruce, Wet
o Field Inspections
•f^f^ 8 "-*"^.
Radies 61
Figure 1-2.
1
1
1
1
A
AA A
AA
Lobaria pulmonaria
A^A A A
A
*
"*
*
'
*
.
A
* » » *'
*
*
1
**
*
A
-
A
A
A
A
A
A
A A
±A A
A
Sticta fulginosa
A AA
A
A *
jA A
A
A
*
•
*
A
A
A
•
A
'
.
•
A
A
•
A
A
.A
'
A
A
'
A
A
*
.
A
A
A
A
A
* *
A
A
*
Nephroma
occultum
A
-
A *
A
: *
A
A
* A
'
AA A
.
-£^\
AA
A
A
*
•
4
f
A
A
A
*
*
A
Pseudocyphellaria
A
anomala -
A A *
f
" A ' '
A
^
A
^
*
•
*
A
A
A
A
A
A
-
*
. A 1
A
A
A
A
A
A
A
A
A
-1.0
-0.5
'
A
Nephroma isidiosum
A
•
». * *
*
^
A
A A '
'
' A * *
*
A
Lobaria retigera
.*.
/
±
A
A A A
A
A
> V- -
AA
^
A4
^
0.0
A
A
0.5
1.0
-0.5
Axisl
Radies 62
0.0
A
A
0.5
1.0
1.5
Figure 1-3.
4
2
0
-2
-4
4
2
O
-2
-4
4
2
0
-2
aria retlgera
Lobaria
•
•
,
,
•
Nephroma
• _ +
•
J-
H
h-
Nephroma
occultum
i
*
1
Platismatia
Peltigera
$
•
4
2
O
-2
-4
1
1
I
$
1-
H
h-
H
H
colllna
^
*
1
H
Sticta
fuliginosa
Sticta
oroborealis
{
1
1-
J * J
1
H
4
2
0
-2
-4
1-
h
H
4
2
0
-2
-4
H
norvegica
H
4
2
0
-2
I ?
I
isidiosum
3
H
4
2
O
-2
-4
I
1
1
1
1
1
Cavern ularia hultenii
dry
w e t Denslo Temp Preclp Solar
cw
Environmental variables
Radies 63
H
X
hw
sx
Figure 2-1.
./"f.-v " V. /•• >'•-'
Interior Cedar Hemlock
> -*; V -y , , J '. >Woaeoclimatic zone "wk" and "vk" \
' M f c . , , " ••••
J ., •;,- i -J
:ttf
>*
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• *•
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'
•
>
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1
Radies 64
Figure 2-2.
* < * - . , - - --,
Interior Cedar Hemlock
latic zone "wk" and "vk" sub variants
logged areas
(approx last SO years)
'
••'•
*
i
y
.•J
#fef!*«J
iipB
. . . . .
• • - * * '
t
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i f . « • v*»- ; ... *>£")••
I
,-?
•*,-S«£5>4 \:4~:
Radies 65
Figure 2-3.
Interior Cedar Hemlock
biogeoclimatic zone "wk" and "vk" sub variants
| Age Class 9
Age Class 8
'">?••'
•'--
-•jesss. Protected Areas
r
favors,'. .••*•.:".'•.
•1* * ; . : - r -
r;
o-
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•-•'-'
U'
. e," .>:
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-»ft.
• * m '
i
-.
Radies 66
Figure 2-4.
0~
4"
wSS^
\
j »
j , SflS vk and IOTvk2
IOT vk2
' : Bio^coclimatk
si
itfc suKkt
is
k****-!
Mm** < #
!»$$#
w«W-
if
mi
mm
, ?3Lrfl%lri» .
t^m%
m
•:sm
~4\*<
' • * &
.iiiii
3KJW
Radies 67
Figure 2-5.
Radies 68
Figure 2-6.
Other Species >140 years
Piceii glaucn \ engclmuniiii, >140 years
Thuja plicatu, >140 years
Tsugu heterophyila, >140 years
Radies 69
Figure 2-7.
Om
20m
40m
Om
10m
30m
50m
Radies 70
70m
90m
100m
Figure 2-8.
Matrix Coding
I Presence • Absence
Information Remaining {%)
0
25
50
75
100
-Q
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tf -CE
^
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i_
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Figure 2-9.
0
2.5
5
10
15
20
25
Tsuga heterophylla 'Dry'
Thuja plicata 'Dry'
Thuja plicata 'Wet'
Tsuga heterophylla 'Wet'
Radies 72
Figure 2-10.
0 2.5 5
™ ™ •"
10
—
15
20
|
25
1^—hn
| Very Low
r~iLo»
^ ^ | Medium
H
Radies 73
Very High
Figure 2-11.
0
2.5
5
10
15
20
25
I
| Very Low
r
i LOW
i m Medium
HHigh
^ | Very High
Radies 74
Figure 2-12.
0
2.5
5
10
15
20
25
|
| Very Low
[ I Low
H B Medium
• B Very High
Radies 75