scholarly journals Causes and amelioration of nutrient deficiencies in cutovers of cedar-hemlock forests in coastal British Columbia

1996 ◽  
Vol 72 (3) ◽  
pp. 293-302 ◽  
Author(s):  
C. E. Prescott ◽  
G. F. Weetman ◽  
J. E. Barker
Keyword(s):  
British Columbia ◽  
Sewage Sludge ◽  
Nutrient Availability ◽  
Nutrient Deficiencies ◽  
Growth Responses ◽  
Old Growth ◽  
Poor Growth ◽  
Ericaceous Shrub ◽  
Forest Floors ◽  
Coastal British Columbia

Poor growth of conifer regeneration occurred on sites formerly occupied by old-growth cedar-hemlock (CH) forests in coastal British Columbia, 5–8 years after clearcutting and slashburning. Symptoms included chlorotic foliage and growth check of Sitka spruce, western hemlock, western red cedar and amabilis fir, coincident with the expansion of the ericaceous shrub, salal, on the cutovers. Fertilization trials identified N and P deficiencies as the cause of the growth check of conifers, and additions of 300 kg N ha−1 and 100 kg P ha−1 significantly improved tree growth rates. Equivalent growth responses were achieved with additions of sewage sludge and fish silage. Burning, cultivating, liming, higher planting densities or herbicide application, were less effective in promoting conifer growth. The nutrient deficiencies in conifers on CH cutovers were the result of two factors: low nutrient availability in soil and humus, and competition and interference from salal. Salal immobilized substantial amounts of N in biomass and an in vitro study suggested it was able to use organic forms of N through its mycorrhizal fungi. The mycorrhizae of salal also interfered with those of hemlock, which further reduced their ability to take up nutrients. High concentrations of phenolic acids were associated with salal, which interfere with mineralization and uptake of N. The low availability of N and P in CH cutovers originated in forest floors of the old-growth forests prior to clearcutting. Nutrient availability was low in all layers of the forest floor in CH forests, and this appeared to result from three main factors. First, cedar litter contains less N and more decay-resistant material than other species, and produces forest floors with low rates of N mineralization. Second, the forest floors in CH forests are wetter and have less soil fauna than in HA forests, leading to incomplete decomposition and mineralization of N. Third, the salal understorey in CH forests interferes with mineralization of N through the production of tannins. Key words: growth check, fertilization, herbicide, ericaceous shrub, sewage sludge, mycorrhizae, allelopathy, nitrogen availability, nutrient cycling, NMR analysis

Effects of fertilization on the nutrition and growth of a slow-growing Engelmann spruce plantation in south central British Columbia

1992 ◽  
Vol 22 (11) ◽  
pp. 1617-1622 ◽  
Author(s):  
R.P. Brockley
Keyword(s):  
British Columbia ◽  
Tree Growth ◽  
Nitrogen Nutrition ◽  
Ferrous Sulphate ◽  
Nutrient Deficiencies ◽  
Height Increment ◽  
Growth Responses ◽  
Poor Growth ◽  
Engelmann Spruce ◽  
South Central

A study was undertaken to investigate the effects of ground and foliar fertilizer applications on the growth of a 15-year-old Engelmann spruce (Piceaengelmannii Parry) plantation in the south central interior of British Columbia. The site had been broadcast burned prior to plantation establishment, and poor growth performance and pretreatment foliar analyses indicated that multiple nutrient deficiencies were likely growth limiting. Fertilization has had a very strong positive influence on height increment and branch elongation. Although growth responses were minimal in the 1st year after treatment, cumulative increases in height increment over the next 2 years averaged 41 cm (range 28–48 cm) greater than those recorded in unfertilized trees. In relative terms, these responses averaged 102% (range 90–120%). Improvements in branch increment over this 2-year period also averaged 102% (range 85–115%). Results indicate that the majority of the growth response has been due to improved nitrogen nutrition. Combined ground applications of nitrogen and a "complete mix" fertilizer were no better than nitrogen alone in stimulating tree growth. The effectiveness of 2% ferrous sulphate and sodium sulphate sprays was probably adversely affected by foliar scorching following spray application. However, despite foliar burning, results indicate that trees may respond favourably to iron applications if accompanied by ground applications of nitrogen and other deficient nutrients (likely sulphur). Because the study design did not allow distinction of cause and effect, with respect to the consequences of the prior broadcast burn, it cannot be stated conclusively that burning is responsible for inadequate stand nutrition and poor tree growth on this site. However, when combined with evidence of impaired nutrition following slash burning from other studies, it may be safely inferred that burning will exacerbate existing nutritional problems and that fertilization under these conditions may at least temporarily improve plantation performance.

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 Twenty-year assessment of four tree species planted in the mountain hemlock zone of coastal British Columbia

2003 ◽  
Vol 79 (2) ◽  
pp. 280-284
Author(s):  
D Burgess ◽  
A K Mitchell ◽  
G Goodmanson
Keyword(s):  
British Columbia ◽  
Seedling Survival ◽  
Field Performance ◽  
High Elevation ◽  
Poor Growth ◽  
Abies Amabilis ◽  
Species Response ◽  
Tsuga Mertensiana ◽  
Abies Procera ◽  
Coastal British Columbia

Concerns about low seedling survival and poor growth in plantations in montane areas resulted in a study to assess the field performance of amabilis fir (Abies amabilis (Dougl. Ex Loud) Dougl. Ex J. Forbes), noble fir (Abies procera Rehd.), yellow cedar (Chamae-cyparis nootkatensis (D. Don) Spach) and mountain hemlock (Tsuga mertensiana (Bong.) Carrière). Seedlings were planted on six sites within the Mountain Hemlock zone of coastal British Columbia. The most recent results, based on a field assessment completed 20 years after the study was started, are presented. Little variation was noted among seedling stock types or between fall and spring planting. Seedling survival was greater than 78% for all four species. Although the sites were initially considered similar, large differences in productivity and species response on the six sites are now evident. Key words: silviculture, high-elevation forestry, montane forests, reforestation, seedling establishment, Abies amabilis, Abies procera, Chamaecyparis nootkatensis, Tsuga mertensiana

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 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

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