Cryptogams on decaying wood in old‐growth forests of southern coastal British Columbia

1999 ◽  
Vol 10 (6) ◽  
pp. 883-894 ◽  
Author(s):  
Hong Qian ◽  
Karel Klinka ◽  
Xianghou Song
Keyword(s):  
British Columbia ◽  
Old Growth ◽  
Old Growth Forests ◽  
Decaying Wood ◽  
Coastal British Columbia

scholarly journals Western redcedar population dynamics in old-growth forests: Contrasting ecological paradigms using tree rings

2003 ◽  
Vol 79 (3) ◽  
pp. 517-530 ◽  
Author(s):  
Lori D Daniels
Keyword(s):  
British Columbia ◽  
Population Dynamics ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
Silver Fir ◽  
Old Growth ◽  
Western Redcedar ◽  
Old Growth Forests ◽  
Gap Phase ◽  
Coastal British Columbia

In coastal British Columbia, late-successional forests dominated by western redcedar (Thuja plicata Donn ex D. Don) are structurally complex, with deep multi-layered canopies, large trees that are > 250 years old, and abundant coarse woody debris (CWD). These forests are presumed to be "old-growth" forests in which fine-scale gaps are the dominant disturbance regime, accounting for their structural diversity. In this study, I have used tree-ring analyses to investigate western redcedar regeneration dynamics in these old-growth forests. Western redcedar dominates canopies of many stands, but is rare in the understorey although it tolerates shade. The traditional interpretation is that western redcedar depends on catastrophic disturbance to regenerate and that it is replaced through succession by western hemlock (Tsuga heterophylla (Raf.) Sarg.) and Pacific silver fir (Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes), which are abundant in the understorey. Dominant trees are perceived to represent an even-aged, post-disturbance cohort and the lack of regeneration indicates a population decline in the absence of catastrophic disturbances. In this paper, I investigate four assumptions underlying this interpretation: (1) Tree size indicates age. (2) Populations establish as even-aged, post-disturbance cohorts. (3) Abundant CWD represents recent mortality. (4) Regeneration is insufficient to maintain canopy dominance. Using tree-ring evidence, I show that population dynamics of western redcedar are a combination of gap-phase establishment and a continuous mode of recruitment from the sub-canopy to the canopy. Specifically, size is a poor surrogate for tree age. Age distributions from 15 sites revealed uneven-aged populations, rather than single post-disturbance cohorts. Both logs and snags of western redcedar may persist more than 270 years; they do not represent recent mortality that is disproportionate to the number of live western redcedar in canopy. The regeneration niches of western redcedar and western hemlock overlap. For both species, gap-phase disturbances result in substrate suitable for successful seedling establishment. Preliminary results from dendroecological analysis of radial growth rates of trees in the subcanopy and canopy strata suggest that western hemlock and Pacific silver fir depend on gaps to recruit to the upper canopy, but recruitment of western redcedar may be independent of canopy gaps. I propose that differences in mode of recruitment to the canopy may explain the differences in population structures between western redcedar, western hemlock, and Pacific silver fir in the old-growth forest. These results provide an ecological precedent for use of a range of silvicultural systems, including clearcuts through single-tree harvesting and protection forests, when managing western redcedar in coastal British Columbia. Key words: Coastal British Columbia, disturbance regimes, regeneration dynamics, Thuja plicata, variable retention silviculture

STUDIES IN FOREST PATHOLOGY: XIV. DECAY OF DOUGLAS FIR IN THE COASTAL REGION OF BRITISH COLUMBIA

1954 ◽  
Vol 32 (5) ◽  
pp. 630-653 ◽  
Author(s):  
G. P. Thomas ◽  
R. W. Thomas
Keyword(s):  
British Columbia ◽  
Coastal Region ◽  
Douglas Fir ◽  
Tree Age ◽  
Separate Analysis ◽  
Average Amount ◽  
Old Growth ◽  
Dead Trees ◽  
Select Group ◽  
Coastal British Columbia

An investigation of Douglas fir, Pseudotsuga taxifolia (Poir.) Britton, in coastal British Columbia has shown that decay losses in old-growth stands are low, amounting to 2.6 and 7.3% of the gross volume of living and combined living and dead trees respectively. Twenty-five decay-producing fungi were isolated from living trees and 29 from dead trees. The most important of these were Fomes pini (Thore) Lloyd, Polyporus schweinitzii Fries, and Fomes pinicola (Sw.) Cke. Certain irregularities in the occurrence of decay-producing fungi and the amounts of decay associated with them were traced to the influences of site, tree age or size, latitude, and stand history. Root infections were the most frequent but branch-stub infections caused the greatest average amount of decay. An examination of tree abnormalities showed that a select group of them, sporophores and swollen knots of Fomes pini in particular, are useful indicators of hidden decay. A separate analysis of dead trees has shown that they occasion ally form a high proportion of Douglas fir stands and that much of the wood in such trees is sound.

scholarly journals Coarse woody debris in the old-growth forests of British Columbia

2003 ◽  
Vol 11 (S1) ◽  
pp. S135-S157 ◽  
Author(s):  
M C Feller
Keyword(s):  
British Columbia ◽  
Coarse Woody Debris ◽  
Functional Role ◽  
Animal Species ◽  
Woody Debris ◽  
Douglas Fir ◽  
Forest Age ◽  
Old Growth ◽  
Old Growth Forests

This paper synthesizes data extracted from the literature and data collected in various studies by the author on the quantity, characteristics, and functional importance of coarse woody debris (CWD) in the old-growth forests of British Columbia (B.C.). There is little agreement in the literature about the minimum diameter of CWD or the number of decay classes recognized. In western North America, five decay classes are commonly used, but recent studies suggest fewer decay classes are preferable. Comparisons among decay classes and biogeoclimatic zones and subzones in B.C. reveal that quantities and volumes are greatest (up to approximately 60 kg/m2 and approximately 1800 m3/ha, respectively), and CWD persists the longest (sometimes in excess of 1000 years) in the Coastal Western Hemlock (CWH) biogeoclimatic zone. The quantity and ground cover of CWD increase with forest productivity. Persistence of CWD has varied from less than 100 to over 800 years in two coastal (CWH and Mountain Hemlock (MH)) and three interior (Interior Douglas-fir (IDF), Interior Cedar–Hemlock (ICH), and Engelmann Spruce – Subalpine Fir (ESSF)) biogeoclimatic zones. Trends in CWD quantity with forest age in managed coastal B.C. forests suggest a U-shaped curve, with greater quantities occurring in recent cutovers than in old-growth forests, and lowest quantities occurring in middle-aged forests. This may be the normal trend in CWD with forest age, with departures from this trend resulting from disturbance- or environment-specific factors. Relatively large amounts of data exist on the characteristics of CWD in the CWH, IDF, ICH, ESSF, and Boreal White and Black Spruce (BWBS) biogeoclimatic zones, but such data for the Coastal Douglas-fir, Sub-Boreal Pine–Spruce, Sub-Boreal Spruce (SBS), and Spruce–Willow–Birch biogeoclimatic zones appear relatively sparse. There have been few studies of the functional role of CWD in B.C. forests, but those studies that have been completed indicate that CWD is an important habitat component for some plant and animal species. A total of 169 plant species, including >95% of all lichens and liverworts, were found to grow on CWD in old-growth forests in the CWH, MH, IDF, ICH, and ESSF biogeoclimatic zones. One third of these species were restricted to CWD. Studies in several biogeoclimatic zones have found that CWD provided preferred habitat for and was associated with higher populations of some small animal species, such as shrews, some voles, and some salamanders, in old-growth forests, but the effects varied with species and biogeoclimatic zone. The nutrient cycling role of CWD is not yet well known, but it currently appears to be relatively insignificant in B.C. old-growth forests. Although it has been considered that CWD could increase mineral soil acidification and eluviation, no evidence for this was found in a study of the CWH, MH, IDF, ICH, ESSF, BWBS, and SBS biogeoclimatic zones. Future studies of the functional role of CWD should consider both scale (square metre vs. hectare) and temporal (changes in CWD with forest age) issues, as studies including these are sparse and both may be important. Key words: biogeoclimatic zones, British Columbia, coarse woody debris, old-growth forests.

Intra-annual variability in isotopic and total nitrogen in tree rings of old growth Sitka spruce from coastal British Columbia

Botany ◽  
2018 ◽  
Vol 96 (12) ◽  
pp. 851-857 ◽  
Author(s):  
T.E. Reimchen ◽  
Estelle Arbellay
Keyword(s):  
British Columbia ◽  
Tree Ring ◽  
Environmental Changes ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Wilcoxon Test ◽  
Old Growth ◽  
Ecological Processes ◽  
Annual Variability ◽  
Coastal British Columbia

Tree-ring studies using increment cores have increasingly measured elemental (N) and isotopic (δ15N) nitrogen values to evaluate environmental changes in the nitrogen cycle. The paucity of nitrogen in wood has constrained tree-ring analyses to annual resolution. Based on 77 rings and 310 sub-rings, we provide evidence for substantial intra-annual variability in N and δ15N values in the heartwood of 11 geographically widely separated, old growth Sitka spruce [Picea sitchensis (Bong.) Carrière] trees from coastal British Columbia. The range of N and δ15N values within rings (intra-annual level) was on average equal to or up to seven-times the range among rings (inter-annual level). Most rings showed a seasonal reduction in N values from early to late growth and a corresponding increase to the early growth of the following season (P < 0.05 to 0.001, Mann–Whitney–Wilcoxon test). By contrast, intra-annual changes in δ15N values were highly variable among years and among trees, ranging from pronounced oscillations (4.0‰) to reasonable consistency. Our results allude to the potential importance of such intra-ring data for interpreting seasonal trends in nitrogen use and increasing understanding of ecological processes in the marine–terrestrial interface.

Population genetic structure of tailed frogs (Ascaphus truei) in clearcut and old-growth stream habitats in south coastal British Columbia

2005 ◽  
Vol 83 (11) ◽  
pp. 1460-1468 ◽  
Author(s):  
T R Wahbe ◽  
C Ritland ◽  
F L Bunnell ◽  
K Ritland
Keyword(s):  
British Columbia ◽  
Genetic Structure ◽  
Population Genetic ◽  
Isolation By Distance ◽  
Physical Distance ◽  
Future Research ◽  
Ecological Data ◽  
Old Growth ◽  
Ascaphus Truei ◽  
Coastal British Columbia

Ascaphus truei Stejneger, 1899 relies on cool, fast-flowing, forested mountain streams, which receive little protection from logging activities. During recovery of post-logging habitats, local extirpation of Ascaphus is a concern because their recolonization may be slow. In British Columbia, Oregon, and California, coastal Ascaphus populations are designated as "at risk". To infer fragmentation impacts from patterns of genetic structure, we used RAPD molecular markers and compared population genetic structures of Ascaphus larvae in an old growth with an adjacent clearcut stream located in coastal British Columbia. In the clearcut, larvae were less genetically diverse than in the old growth and exhibited no relationship between physical distance and genetic relatedness, whereas in the old growth, genetic similarity decreased with physical distance. Patterns of gene flow between the clearcut and old-growth streams were significantly different. The clearcut population went through a bottleneck/founding event, but also exhibited greater dispersal. The frogs were perhaps searching for new habitat (which would lower isolation by distance) and suffering mortality (which would decrease diversity). Most problems in conservation will require genetic and ecological data, and future research should aim to incorporate methodologies from both fields.

scholarly journals Managing second-growth forests as caribou habitat

Rangifer ◽  
1990 ◽  
Vol 10 (3) ◽  
pp. 139 ◽  
Author(s):  
Susan K. Stevenson
Keyword(s):  
British Columbia ◽  
Habitat Management ◽  
Rangifer Tarandus ◽  
Management Practices ◽  
Rangifer Tarandus Caribou ◽  
Woodland Caribou ◽  
Old Growth ◽  
Stand Management ◽  
Second Growth ◽  
Old Growth Forests

Habitat management for woodland caribou (Rangifer tarandus caribou) in southeastern British Columbia has generally focussed on protecting old-growth forests from logging. As that strategy becomes more difficult to maintain, biologists are beginning to explore opportunities to manage second-growth stands to provide arboreal lichens and other habitat resources important to caribou. Special harvesting and stand management practices are being developed and formulated into strategies for maintaining caribou populations in managed stands.

Activity levels of Marbled Murrelets in different inland habitats in the Queen Charlotte Islands, British Columbia

1993 ◽  
Vol 71 (5) ◽  
pp. 977-984 ◽  
Author(s):  
Michael S. Rodway ◽  
Heidi M. Regehr ◽  
Jean-Pierre L. Savard
Keyword(s):  
British Columbia ◽  
High Elevation ◽  
Activity Levels ◽  
Old Growth ◽  
Marbled Murrelet ◽  
Queen Charlotte Islands ◽  
Old Growth Forest ◽  
Second Growth ◽  
Old Growth Forests ◽  
Marbled Murrelets

We compared Marbled Murrelet (Brachyramphus marmoratus) activity levels in May, June, and July 1990 in four habitats in the Queen Charlotte Islands, British Columbia: alpine, old-growth forest at high elevation, old-growth forest at low elevation, and second-growth forest. The number of Marbled Murrelet detections was highest in old-growth forests. In alpine areas, small numbers of murrelet detections were mostly of distant birds flying over low-elevation forest. Numbers of detections were higher in low-elevation than in high-elevation old-growth forests in May and July, but not in June. Proportions of detections within smaller radii of survey stations were higher in low elevation forest in all months. The highest activity levels were associated with old-growth forest stands of large Sitka spruce (Picea sitchensis) and western hemlock (Tsuga heterophylla). The few detections that occurred in second-growth forests were mostly of distant birds. Stations in second-growth forest close to stands of old-growth forest had more frequent detections than stations with no old-growth forest nearby. Our results support the association of Marbled Murrelets with old-growth forests. Limitations of the survey methodology are discussed.

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