Interior Cedar-hemlock Forests Research Articles

Forest vegetation change and disturbance interactions over the past 7500 years at Sasquatch Lake, Columbia Mountains, western Canada

Fire is the most important abiotic disturbance in the interior cedar-hemlock (ICH) and Engelmann spruce–subalpine fir (ESSF) forest zone of southeastern British Columbia, Canada. Other disturbances are also important, such as defoliator and boring insect outbreaks, windthrow, diseases, and rapid mass movements. Few studies have examined the interaction between multiple types of disturbances in these forests over long timescales. Here we present high-resolution analyses of biomass burning, erosion, and vegetation assemblage changes at Sasquatch Lake (NEL02), a valley lake in the Columbia Mountains. The 531.5 cm sediment core was radiocarbon dated and provided a 7500-year stratigraphy that was used for pollen, macroscopic charcoal (>150 μm), and sedimentologic analyses. Pollen and charcoal data provided evidence of forest composition changes and fire activity. Magnetic susceptibility, loss-on-ignition, and particle size distribution analyses characterised changes in erosion into the basin. The results show that coniferous forests, with a high abundance of Pinus pollen, had established in the catchment by the beginning of the record and were subject to intermittent burning and high-energy erosive events. Tsuga heterophylla expanded by 4400 cal BP and the modern interior cedar-hemlock forests expanded throughout the lower elevations due to increased regional continentality since 4500 cal BP. High-energy erosional inputs to the lake were less frequent from 3500 to 750 cal BP and rapid mass movements may have increased in frequency during the Little Ice Age. Dendrochronological evidence in these stands suggests a mixed-severity fire regime during past ∼300 years, which has not been fully examined for charcoal-based fire event reconstruction. Here we use identified peaks as an indicator of increased biomass burning and charcoal movement in the catchment in relation to peaks in allochthonous clastic material to understand the potential relationships between biomass burning and erosion events at multiple temporal scales in the catchment. This suggests that post-fire conditions, up to several decades, were subject to increased erosion to the lake and erosion events were more common during the early Holocene. Establishment of dense ESSF and ICH forests decreased siliciclastic input to the lake throughout the mid Holocene until a recent rockslide. The high-resolution sampling of this lake sediment record provides long-term evidence of variability in the relationships between vegetation cover, fire and erosion at a catchment scale.

Macrolichen diversity as an indicator of stand age and ecosystem resilience along a precipitation gradient in humid forests of inland British Columbia, Canada

The distributional ecology of 87 macrolichens is reported from 14 unmanaged mid-seral and old forest stands along a precipitation gradient in south-central British Columbia. We used a combination of univariate and multivariate statistics to investigate the role of forest structure and stand age in the distribution of epiphytic macrolichens in interior cedar-hemlock forests. Old forests support a higher number of species; although mean species richness is not significantly different between the two age classes. Terricolous and epixylic community structure is correlated with stand age and log characteristics, but the epiphtytic community is not. Epiphytic community structure is strongly associated with precipitation in the old stands, but not in the mid-seral stands. Old forests at the wetter end of the precipitation gradient contained several old-growth associated species, all of which are hygrophytic. Most epiphytic macrolichens associated with old forests are not dependent on specific structural attributes. However, western red cedar (Thuja plicata Donn ex D. Don) harbors the greatest number of arboreal macrolichen species by far in these unmanaged stands and should, therefore, be considered a key indicator in managed forests. Our study suggests that most macrolichen species found in old forests can also occur in 70- to 165-year-old forests dating from stand-replacing fires. Old forests, however, clearly provide important habitat for oceanic epiphytes at the edge of their ecological range in the interior of British Columbia. Our findings illustrate that the macrolichen flora in wet toe-slope stands in humid inland British Columbia has a high level of resilience following disturbance under natural succession conditions. It also underlines the point that some species, like Lobaria pulmonaria, are good indicators of old-growth forests in certain regions but not in others, suggesting a careful use of the term old-growth dependence.

Decline of planted lodgepole pine in the southern interior of British Columbia

Lodgepole pine is extensively planted across western Canada but little is known about development of these stands beyond the juvenile stage. We quantified stocking status and damage incidence in sixty-six 15- to 30-year-old lodgepole pine plantations that had previously been declared free-growing in the southern interior of British Columbia. The stands were located in six biogeoclimatic zones: Engelmann Spruce-Subalpine Fir (ESSF), Montane Spruce (MS), Interior Cedar-Hemlock (ICH), Interior Douglas-fir (IDF), Sub-Boreal Spruce (SBS), and Sub-Boreal Pine-Spruce (SBPS). Free-growing standards were no longer met on 27% of plantations, with the worst performance (70% no longer free-growing) in the Interior Cedar-Hemlock forests. Natural regeneration was common but it was half the size of lodgepole pine. Biotic damage, especially hard pine stem rusts, was the dominant factor reducing free-growing densities. Stands were at greater risk of reduced stocking where summer precipitation was higher or soil moisture regimes were wetter and where stands had been broadcast-burned prior to planting or received secondary treatments of brushing or pruning. Reforestation policies that encourage widespread planting of lodgepole pine, particularly in areas where lodgepole pine has limited natural occurrence such as in the ICH zone, should be reconsidered given that health problems are extensive and are expected to increase with climate change.Key words: Pinus contorta, lodgepole pine, free-growing, stocking, forest health, damage, disease

Influence of soil nutrients on ectomycorrhizal communities in a chronosequence of mixed temperate forests

Many factors associated with forests are collectively responsible for controlling ectomycorrhizal (ECM) fungal community structure, including plant species composition, forest structure, stand age, and soil nutrients. The objective of this study was to examine relationships among ECM fungal community measures, local soil nutrients, and stand age along a chronosequence of mixed forest stands that were similar in vegetation composition and site quality. Six combinations of age class (5-, 26-, 65-, and 100-year-old) and stand initiation type (wildfire and clearcut) were replicated on four sites, each representing critical seral stages of stand development in Interior Cedar-Hemlock (ICH) forests of southern British Columbia. We found significant relationships between ECM fungal diversity and both available and organic P; available P was also positively correlated with the abundance of two ECM taxa (Rhizopogon vinicolor group and Cenoccocum geophilum). By contrast, ECM fungal diversity varied unpredictably with total and mineralizable N or C to N ratio. We also found that soil C, N, available P, and forest floor depth did not exhibit strong patterns across stand ages. Overall, ECM fungal community structure was more strongly influenced by stand age than specific soil nutrients, but better correlations with soil nutrients may occur at broader spatial scales covering a wider range of site qualities.

Trade-offs between competition and facilitation: a case study of vegetation management in the interior cedar–hemlock forests of southern British Columbia

Vegetation-management practices are applied in temperate-zone forests on the assumption that changing the competitive environment between conifers and unwanted vegetation will improve conifer productivity. We review this assumption using research examining interactions between paper birch (Betula papyrifera Marsh.) and conifers in the highly productive Interior Cedar Hemlock zone of British Columbia. We have found that both competition and facilitation are important in young plantations, where paper birch competes for light, reducing growth of shade-intolerant conifers, but having a facilitative effect on shade-tolerant conifers. This facilitative effect may result from greater ectomycorrhizal diversity, population sizes of Armillaria ostoyae (Romagn.) Herink antagonistic bacteria, and associative nitrogen fixation in plantations where interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) is mixed with paper birch. Where paper birch is manually cut or girdled, conifers grow faster in diameter, but more die as a result of A. ostoyae root disease, and these responses increase with increasing weeding intensity. The weeding treatments do not affect plant community species richness but reduce paper birch dominants and increase understory structural diversity. British Columbia forest policy has been slow to respond to these findings, and we suggest that as a result, the forested landscape incurs substantial risk. We propose additional pathways for managing Interior Cedar Hemlock mixtures to ensure that the natural mix of forest types in the landscape is maintained.

Soil resources and the growth and nutrition of tree seedlings near harvest gap – forest edges in interior cedar–hemlock forests of British Columbia

Observations of tree seedlings with chlorotic foliage and stunted growth near harvest gap – forest edges in interior cedar–hemlock forests inspired a study addressing the following questions: (1) Do seedling foliar chemistry, foliar nitrogen (N) versus growth relationships, and fertilizer responses suggest N-limited seedling growth? (2) Are patterns in soil characteristics consistent with N limitation, and can interrelationships among these characteristics infer causality? Our results suggest that seedling growth near gap–forest edges was colimited by N and light availability. Soil mineral N and dissolved organic N (DON) concentrations, in situ net N mineralization, and water generally increased from forest to gap, whereas N mineralization from a laboratory incubation and total N and carbon did not vary with gap–forest position. Interrelations among variables and path analysis suggest that soil water and total soil N positively affect DON concentration and N mineralization, and proximity to mature gap–forest edge trees negatively impacts mineral N concentration and water. Collectively, our results suggest that soil N levels which limit seedling growth near gap edges can be partially explained by the direct negative impacts of gap–forest edge trees on mineral N concentrations and their indirect impacts on N cycling via soil water, and not via effects on substrate chemistry.

Retention of canopy lichens after partial-cut harvesting in wet-belt interior cedar–hemlock forests, British Columbia, Canada

Old-growth cedar–hemlock forests of the interior wet-belt of British Columbia are rich in abundance and diversity of canopy lichens, but are subject to forest harvesting. If these distinctive canopy lichen communities are to be conserved, it is important to learn how they are affected by forestry practices, including partial-cutting techniques designed to retain old-growth attributes. The retention of canopy lichens after 30 and 70% partial-cut harvesting (immediate post-harvest and 2-year post-harvest measurements) was examined using direct canopy access methods (tree climbing) in two old-growth interior cedar–hemlock forest stands of the upper Fraser River valley. Mean lichen loading was generally lower in all treatment areas, including control sites, 2 years after harvesting. However, three of four lichen-sampling groups (cyanolichen, foliose, and Bryoria group lichens) did not show significant treatment effects (total lichen loading) by harvesting type (30, 70 or 100% retention), when data sets were standardized against initial post-harvest lichen loading. Only in Alectoria group lichens were treatment effects observed. Although cyanolichen loading was not significantly different in retained trees in most harvest blocks, many thalli, especially those near south-facing edges, were discolored, suggesting that future cyanolichen loading may be lower within partial-cut harvest blocks. Litterfall in general was greater during 2001/2002 than 2002/2003, even in the control units, suggesting weather-related differences between years. For Alectoria, there appeared to be a treatment-related pulse of litterfall that was more pronounced in the 70% removal than the 30% removal treatment unit. Deposition patterns of litterfall components in relation to edges of openings indicated a heightened level of Alectoria litterfall along edges. Treatment-related differences were absent or weak in other groups, and cyanolichen litterfall did not differ between years in any study area/treatment unit combination. These findings suggest that lichen retention in the residual stand of both partial-cut treatments was adequate to meet management goals, but also point to the necessity of future monitoring, as other edge effects (e.g. microclimate changes) influence future lichen growth and mortality.

Lobaria pulmonaria abundance as an indicator of macrolichen diversity in Interior Cedar–Hemlock forests of east-central British Columbia

Orographic precipitation over interior mountains has resulted in the formation of the inland temperate rainforest, where certain stands are potentially antique and support a rich flora of epiphytic macrolichens. We documented macrolichen diversity across three age-classes in forests of the Interior Cedar–Hemlock biogeoclimatic zone (i.e., ICHwk3 subzone) east of Prince George, British Columbia. Our objectives were to report changes in lichen communities with stand age, identify potential indicators of antiquity, and investigate the functional role of dominant species in the ecosystem. We identified 41 taxa, including 4 alectorioid lichens, 21 foliose chlorolichens, and 16 old-growth-associated chlorolichens and cyanolichens. Older forests supported more species than young or mature forests. The abundance of Lobaria pulmonaria (L.) Hoffm. was strongly correlated with this increase in diversity and may therefore be an appropriate indicator of stand age in the ICH. The increase in L. pulmonaria and other N2-fixing cyanolichens with stand age may have significant implications for forest nitrogen budgets in the interior of British Columbia, where atmospheric nitrogen deposition is relatively low and biological N2 fixation accounts for nearly all of the nitrogen lost to forest harvesting. We hope that this greater understanding of lichen ecology across age-classes will promote sustainable stewardship of the remaining old-growth forests of inland British Columbia.Key words: macrolichen diversity, Interior Cedar–Hemlock zone, Lobaria pulmonaria, indicator species, cyanolichens, stand age.

Paper birch competitive effects vary with conifer tree species and stand age in interior British Columbia forests: implications for reforestation policy and practice

Paper birch ( Betula papyrifera Marsh) is considered the most important competitive threat to commercially valuable conifers in the highly productive interior cedar–hemlock forests of British Columbia. It is routinely removed from conifer plantations at high cost to increase conifer growth rates and meet reforestation policy regulations. Competitive effects of paper birch and other neighbours on conifer growth were measured in mixed forests to test the hypotheses that the importance and intensity of interspecific competition were (a) high in young plantations; (b) decrease with stand age; (c) decrease with conifer species shade tolerance. Neighbourhood analysis was applied to 748 target conifer trees in 11 stands that included three stand age classes (11, 25, and 50 years-old) and three target conifer species (Douglas-fir ( Pseudotsuga menziesii Mirb. Franco), western redcedar ( Thuja plicata D. Don), and western larch ( Larix occidentalis Nutt.)). All sites had similar site characteristics and disturbance histories. Regression models were used to examine the importance (model adjusted r 2) and intensity (model β 1) of neighbour competition on target conifer size. Double logarithmic regression models explained on average 38±3% of the variation in target conifer diameter from the neighbourhood index, NRI ( neighbour relative height index )=∑(( neighbour basal area × height)/ target conifer height ) . The models indicated that broadleaf neighbours were more important and intense competitors in the 11- and 25-year-old stands, and conifers were more important and intense competitors in the 50-year-old stands. When all broadleaf and conifer neighbours were included in the models, the intensity and/or importance of neighbour competition decreased in the order of 25>50>11-year-old stands, and western larch>Douglas-fir>western redcedar. Instead of encouraging uniform broadleaf removal across most conifer plantations in the BC interior, reforestation policies should take into account the variable effects of broadleaf competition within stands, across stand ages, and with different tree species compositions.

Assessment of interspecific competition using relative height and distance indices in an age sequence of seral interior cedar–hemlock forests in British Columbia

Treatments that reduce neighbour density are widely applied in the belief they will improve conifer growth in mixed forests. However, our understanding of stand composition and age effects on competition is poor. We used neighbourhood analysis for 748 target conifer trees to examine interspecific competition within 11-, 25-, and 50-year-old mixed, even-aged stands of paper birch (Betula papyrifera Marsh.), Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), western redcedar (Thuja plicata Donn ex D. Don), and western larch (Larix occidentalis Nutt.) in southern interior British Columbia. Critical neighbourhood height and distance were identified where competition accounted for the greatest variation in target conifer diameter. Competition processes were emperically examined using relative height indices. We found that critical neighbourhood distance increased with stand age and was greater for larch than for cedar. Critical neighbourhood height was higher for cedar than for Douglas-fir or larch in the 11-year-old stands but lower in the older stands. The most important competitors in the 11-year-old stands were tall neighbours, whereas those in the older stands were short neighbours. We found asymmetrical relationships between target conifers and neighbours for all species and age-classes, indicating a resource preemption mode of competition. To be useful in developing prescriptions for competition management in mixed species stands, competition indices should consider neighbour identity and critical height for each target species. Assessment radius must also be sufficiently large to adequately characterize competition.

Macrolichen colonization on 120–140 year old Tsuga heterophylla in wet temperate rainforests of central-interior British Columbia: a comparison of lichen response to even-aged versus old-growth stand structures

Canopy lichen abundance was assessed by size class on regenerating hemlocks, comparing trees of similar size and age (c. 120–140 yrs) growing in the understorey of old-growth cedar-hemlock stands with those growing in adjacent even-aged hemlock stands (natural origin patches c. 1–3 ha in size). Five chlorolichen taxa were associated with old-growth understorey trees: Cavernularia hultenii, Hypogymnia vitatta, Parmelia hygrophila, Platismatia norvegica, and Usnea spp. Lobaria pulmonaria was the most abundant cyanolichen on regenerating hemlock in the old-growth forest stands, particularly in lower canopy (under 12 m) exposures. However, other cyanolichen taxa such as Nephroma helveticum, Sticta fulginosa, and Pseudocyphellaria anomala, reached their greatest abundance at mid-canopy (12–24 m) positions. Smaller cyanolichen thalli (<9 cm2) were abundant on regenerating hemlocks across all canopy positions in the old-growth forest, raising the question as to whether or not cyanolichen thalli in mid- to upper-canopy environments represented long-established individuals facing severe growth constraints, or were simply thalli that had experienced higher rates of fragmentation, and thus did not achieve larger sizes. In comparison, cyanolichens of all taxa were essentially absent from the small-patch even-aged forest stands. Given that dispersal of propagules was not likely a major limiting factor, these 120–140 year old even-age stands may not yet have attained sufficient old-growth characteristics (especially canopy microclimate and canopy throughflow enrichment) to support cyanolichen growth. These findings have major conservation biology implications for wet interior cedar-hemlock forests in British Columbia, where forest harvesting is creating a mosaic of even-aged stands, whose projected age at the time of next harvest (rotation age) will be 120 years or less.

Ecological descriptions of pine mushroom ( Tricholoma magnivelare) habitat and estimates of its extent in northwestern British Columbia

Twenty-one sites known to be highly productive pine mushroom ( Tricholoma magnivelare [Peck] Redhead) habitat were described in northwest British Columbia. Soils were well to very rapidly drained and generally coarse in texture, often with a high coarse fragment content and thin forest floor. Western hemlock ( Tsuga heterophylla [Raf.] Sarg.) was consistently the dominant tree species, and lodgepole pine ( Pinus contortavar. latifolia Engelm) was frequently, though not always, present in the tree layer. Plant communities typically featured sparse herb and shrub layers, and a high coverage of mosses. Using the British Columbia biogeoclimatic system of ecosystem classification, all sites in the interior cedar hemlock forests were classified as the (01) Hw-step moss site series, submesic phase, and in the coastal western hemlock forests, as the (03) HwPl-feathermoss site series. Four separate areas of interior cedar hemlock forests, encompassing approximately 60,000 ha were assessed using air photography for the described (01) Hw-step moss submesic habitat. The extent of the submesic habitat across study areas ranged from 4.3 to 21.5% of the hemlock forests. The relatively low areal extent of these valuable forests demonstrated the need to better protect and manage the pine mushroom resource.

Seed abundance versus substrate limitation of seedling recruitment in northern temperate forests of British Columbia

We examine the influence of (i) the spatial distribution and abundance of parent trees (as seed sources) and (ii) the abundance and favourability of seedbed substrates, on seedling recruitment for the major tree species in northwestern interior cedar-hemlock forests of British Columbia, under four levels of canopy openness (full canopy, partial canopy, large gap, and clearcut). Substrate distribution varied with canopy openness, and substrate favourability was a function of both canopy openness and seedling species. Lack of suitable substrates was the predominant factor limiting seedling density under full canopies. Partial canopy and gap sites provided a broad range of favourable substrates in close proximity to parent trees, resulting in the highest observed seedling densities. There was much higher effective dispersion of seedlings away from parent trees in gaps than in the partially cut stands. Seedling dispersion to clearcut sites was poor with seedlings being tightly restricted to a narrow band along the forest edge. Thus, seedling recruitment in these forests was a reflection of the interaction between the abundance of seed and substrate favourability, and the relative importance of these factors varied significantly with canopy structure.

Seed abundance versus substrate limitation of seedling recruitment in northern temperate forests of British Columbia

We examine the influence of (i) the spatial distribution and abundance of parent trees (as seed sources) and (ii) the abundance and favourability of seedbed substrates, on seedling recruitment for the major tree species in north - western interior cedar-hemlock forests of British Columbia, under four levels of canopy openness (full canopy, partial canopy, large gap, and clearcut). Substrate distribution varied with canopy openness, and substrate favourability was a function of both canopy openness and seedling species. Lack of suitable substrates was the predominant factor limiting seedling density under full canopies. Partial canopy and gap sites provided a broad range of favourable substrates in close proximity to parent trees, resulting in the highest observed seedling densities. There was much higher effective dispersion of seedlings away from parent trees in gaps than in the partially cut stands. Seedling dispersion to clearcut sites was poor with seedlings being tightly restricted to a narrow band along the forest edge. Thus, seedling recruit - ment in these forests was a reflection of the interaction between the abundance of seed and substrate favourability, and the relative importance of these factors varied significantly with canopy structure.

Measurement and modeling of spatially explicit variation in light transmission through interior cedar-hemlock forests of British Columbia

We have characterized canopy geometry and light transmission by the nine dominant conifer and broad-leaved tree species of the interior cedar-hemlock (ICH) forests of northern British Columbia. Our field data were used to parameterize a spatially explicit model of light transmission through mixed-species forests. That model, a component of the forest dynamics simulator SORTIE, was developed for eastern deciduous forests, and this paper presents a test of that model in a very different ecosystem. Our results show that individual crowns of the ICH forests intercepted much more light than species of eastern deciduous forests but that the canopy as a whole allowed greater light penetration, largely because of openings between the relatively narrow, conical crowns of the western conifers. Light transmission by individual crowns was correlated with shade tolerance among the conifers (as in eastern deciduous species), but crown depth was not (in contrast with eastern species). Despite the fundamental differences in the nature of light transmission in the two ecosystems, the SORTIE light model developed for eastern deciduous forests was effective at predicting spatial variation in understory light levels in these western coniferous forests. The goodness of fit of such a simple model suggests that the most important factors regulating spatial variation in understory light levels in these forests are simply the sizes and distribution of nearby trees, and the local sky brightness distribution. Discrete canopy gaps represent a special case in which a region of the canopy is not occupied by crowns.

Species richness of ectomycorrhizal fungi in cutblocks of different sizes in the Interior Cedar-Hemlock forests of northwestern British Columbia: sporocarps and ectomycorrhizae

We investigated the species richness of ectomycorrhizal fungi based on epigeous sporocarps in an Interior Cedar-Hemlock forest in northwestern British Columbia in gap sizes of 49-4526 m2, 3-4 years following harvest. We also determined ectomycorrhizal diversity on Pinus contorta var. latifolia Engelm. and Tsuga heterophylla (Raf.) Sarg. seedlings 2 years after outplanting. Ectomycorrhizal fungal richness, based on epigeous sporocarps, decreased exponentially as gap size increased. There were sporocarps of 15 species along 475 m of transect in gaps larger than 900 m2, which was approximately 13% of the number of species present in neighboring forests (115 species along 300 m of transect). These data have implications for foresters who would be interested in managing forests for both timber and edible mushroom harvesting. Ectomycorrhizal richness on seedlings decreased slightly at increasing distances from the edge of the intact forest. The maximum richness was found at 7 m or less from the forest edge for both tree species. The decrease in richness with distance from the forest was associated with an increase in the proportion of Thelephora mycorrhizae in the samples. The number of types of ectomycorrhizae on root systems and the number of species producing epigeous sporocarps were not correlated. These results confirm the importance of sampling both sporocarps and root tips to achieve an accurate estimate of the ectomycorrhizal fungal community in forest ecosystems.

Growth of planted tree seedlings in response to ambient light levels in northwestern interior cedar-hemlock forests of British Columbia

Insights into field-planted conifer seedling growth were gained by fitting height and diameter growth to relative irradiance over the growing season using Michaelis-Menten functions. There was little difference among tree species (Abies lasiocarpa (Hook.) Nutt., Picea glauca (Moench) Voss × Picea sitchensis (Bong.) Carr., Pinus contorta Dougl. ex Loud., Thuja plicata Donn ex D. Don, Tsuga heterophylla (Raf.) Sarg.) in response to ambient light. No significant differences in whole-plant compensation points were observed among species but the ranking of species' compensation points was consistent with their shade-tolerance ranking. Five years after planting, total size and recent growth rates varied little among species from low to high light, implying an absence of trade-offs in low- and high-light growth strategies. Thuja plicata had the greatest response to increased light under deep shade (<20% relative irradiance). All species increased growth above 40% relative irradiance, with no clear whole-plant light saturation point evident under field conditions. Growth rates at high light were broadly overlapping and varied considerably within species. As expected,Pinus contorta growth exceeded that of other species above 70% relative irradiance, but it also exhibited high growth rates at low light. Greatest variability among species was at intermediate light levels (30-70% relative irradiance) where careful matching of tree species to light environment can maximize growth rates.

Species richness of ectomycorrhizal fungi in cutblocks of different sizes in the Interior Cedar-Hemlock forests of northwestern British Columbia: sporocarps and ectomycorrhizae

Species richness of ectomycorrhizal fungi in cutblocks of different sizes in the Interior Cedar-Hemlock forests of northwestern British Columbia: sporocarps and ectomycorrhizae

Growth of planted tree seedlings in response to ambient light levels in northwestern interior cedar-hemlock forests of British Columbia

Growth of planted tree seedlings in response to ambient light levels in northwestern interior cedar-hemlock forests of British Columbia

Measurement and modeling of spatially explicit variation in light transmission through interior cedar-hemlock forests of British Columbia

Measurement and modeling of spatially explicit variation in light transmission through interior cedar-hemlock forests of British Columbia