Using height growth to model local and regional response of trembling aspen (Populus tremuloides Michx.) to climate within the boreal forest of western Québec

2012 ◽  
Vol 243 ◽  
pp. 123-132 ◽  
Author(s):  
Kenneth A. Anyomi ◽  
Frédéric Raulier ◽  
Daniel Mailly ◽  
Martin P. Girardin ◽  
Yves Bergeron
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Height Growth ◽  
Trembling Aspen

Mixed-species effect on tree aboveground carbon pools in the east-central boreal forests

2010 ◽  
Vol 40 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Xavier Cavard ◽  
Yves Bergeron ◽  
Han Y.H. Chen ◽  
David Paré
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Mixed Forest ◽  
Jack Pine ◽  
Carbon Gain ◽  
Trembling Aspen ◽  
Niche Complementarity ◽  
Aboveground Carbon

This study investigates the potential of mixed forest stands as better aboveground carbon sinks than pure stands. According to the facilitation and niche complementarity hypotheses, we predict higher carbon sequestration in mature boreal mixedwoods. Aboveground carbon contents of black spruce ( Picea mariana (Mill.) Britton, Sterns, Poggenb.) and trembling aspen ( Populus tremuloides Michx.) mixtures were investigated in the eastern boreal forest, whereas jack pine ( Pinus banksiana Lamb.) and trembling aspen were used in the central boreal forest. No carbon gain was found in species mixtures; nearly pure trembling aspen stands contained the greatest amount of aboveground carbon, black spruce stands had the least, and mixtures were intermediate with amounts that could generally be predicted by linear interpolation with stem proportions. These results suggest that for aspen, the potentially detrimental effect of spruce on soils observed in other studies may be offset by greater light availability in mixtures. On the other hand, for black spruce, the potentially beneficial effects of aspen on soils could be offset by greater competition by aspen for nutrients and light. The mixture of jack pine and trembling aspen did not benefit any of these species while inducing a loss in trembling aspen carbon at the stand level.

scholarly journals Breeding Bird Communities in Boreal Forest of Western Canada: Consequences of “Unmixing” the Mixedwoods

The Condor ◽  
2000 ◽  
Vol 102 (4) ◽  
pp. 759-769 ◽  
Author(s):  
Keith A. Hobson ◽  
Erin Bayne
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Pinus Banksiana ◽  
Deciduous Forest ◽  
Black Spruce ◽  
Bird Species ◽  
White Spruce ◽  
Trembling Aspen ◽  
Vegetation Heterogeneity ◽  
Mixedwood Stands

Abstract Silvicultural practices following clearcutting in boreal forest may encourage the creation of monospecific, single-aged stands having less vegetation heterogeneity and diversity than original stands. We conducted point counts in central Saskatchewan, Canada, 1993–1995, in pure and mixedwood stands dominated by black spruce (Picea mariana), jackpine (Pinus banksiana), trembling aspen (Populus tremuloides), or white spruce (Picea glauca). Mixedwood stands supported more individuals and more species than pure stands. Higher abundance in mixedwood stands relative to pure stands was consistent among nesting guilds and migration strategies. Rarefaction revealed similar patterns, although pure trembling aspen stands were predicted to support more species than aspen-dominated mixedwood stands. Increased avian diversity in mixedwood stands was not solely the result of the mixing of bird species associated with coniferous or deciduous forest types. Chipping Sparrow (Spizella passerina), Pine Siskin (Carduelis pinus), White-winged Crossbill (Loxia leucoptera), Red-breasted Nuthatch (Sitta canadensis), Swainson's Thrush (Catharus ustulatus), and Tennessee Warbler (Vermivora peregrina) were more abundant in mixedwood stands than pure stands. Black-throated Green Warbler (Dendroica virens), Magnolia Warbler (D. magnolia), and Blackburnian Warbler (D. fusca) were abundant in stands dominated by white spruce but were absent from jackpine or black spruce. Other species such as American Redstart (Setophaga ruticilla) and Chestnut-sided Warbler (D. pensylvanica) relied exclusively on pure trembling aspen, particularly stands with dense shrub cover. Several bird species in the boreal forest will be adversely affected by forestry practices that target mature to old aspen and white spruce mixedwoods and promote reduction in mixedwood compositions of regenerating stands.

Effects of fertilization on decomposition rate of Populus tremuloides foliar litter in a boreal forest

1999 ◽  
Vol 29 (3) ◽  
pp. 393-397 ◽  
Author(s):  
C E Prescott ◽  
R Kabzems ◽  
L M Zabek
Keyword(s):  
Boreal Forest ◽  
Mass Loss ◽  
Litter Decomposition ◽  
Populus Tremuloides ◽  
Decomposition Rate ◽  
Average Rate ◽  
Trembling Aspen ◽  
Single Fertilization

Rates of mass loss of foliar litter of trembling aspen (Populus tremuloides Michx.) were measured for 4 years after a single fertilization with N at 200 kg N/ha or a mix of N, P, K. Ca, Mg, S, and B. Foliar litter from fertilized plots had higher N concentrations than litter from control plots; litter from the nutrient-mix plots had higher concentrations of N, P, and Ca. The average rate of mass loss of aspen foliar litter was 60% after 4 years. The higher concentrations of nutrients in litter from fertilized plots did not affect the rate of decomposition. There was some difference in rates of decomposition of litter incubated in plots of the three treatments. Mass loss was significantly slower in the nutrient-mix plots after 12 and 18 months compared with control plots. This experiment provided no evidence that fertilization of boreal aspen forests will increase rates of litter decomposition.

scholarly journals Stand-level Attributes of Snowshoe Hare (Lepus americanus) Habitat in a Post-Fire Trembling Aspen (Populus tremuloides) Chronosequence in Central Yukon

2013 ◽  
Vol 126 (4) ◽  
pp. 295 ◽  
Author(s):  
Wayne L. Strong ◽  
Thomas S. Jung
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Large Scale ◽  
Global Climate ◽  
Canopy Cover ◽  
White Spruce ◽  
Lepus Americanus ◽  
Snowshoe Hare ◽  
Trembling Aspen ◽  
Understory Shrubs

Large-scale fires are anticipated to increase in frequency in the boreal forest under global climate warming scenarios. To understand concomitant responses by wildlife to fire-induced habitat changes, fecal pellet counts were used to assess Snowshoe Hare (Lepus americanus) use of four age-classes of boreal forest after fire in central Yukon, Canada. Use of stands across a chronosequence of 8–177 years was bimodal. Post-fire Trembling Aspen (Populus tremuloides) stands ≤20 years old had greater densities of Snowshoe Hare pellets (median 156 pellets/dam2) than Trembling Aspen stands 21–70 years old, mixedwood stands 71–120 years old (<17 pellets/dam2), or Western White Spruce (Picea albertiana) -dominated stands 121–170 years old (71 pellets/dam2). Forty stand-level compositional and structural variables were assessed as possible predictors of Snowshoe Hare pellet densities. Multidimensional scaling was used to identify variables (n = 10) that were most strongly related to pellet densities and was followed by multiple regression. Canopy cover of Trembling Aspen <50 cm tall and Western White Spruce ≤1 m tall, and deadfall depth, in combination, were the best estimators of Snowshoe Hare pellet densities among stands in the chronosequence (P <0.001, 64.5% variance explained). Although Trembling Aspen <50 cm tall explained the most variance, its canopy cover did not exceed 10%. More Trembling Aspen cover <50 cm tall and greater deadfall depths within the chronosequence were associated with stands ≤20 years old. Peak Snowshoe Hare use occurred in early (≤20 years old) rather than mid-successional (21–120 years old) stands, contrary to use patterns reported elsewhere. The lack of tall understory shrubs likely limited the use of mid-successional stands.

Compatible diameter and height increment models for lodgepole pine, trembling aspen, and white spruce

2009 ◽  
Vol 39 (1) ◽  
pp. 180-192 ◽  
Author(s):  
Thompson K. Nunifu
Keyword(s):  
Populus Tremuloides ◽  
Lodgepole Pine ◽  
Volume Growth ◽  
White Spruce ◽  
Height Growth ◽  
Stem Density ◽  
Average Height ◽  
Height Increment ◽  
Trembling Aspen ◽  
Diameter Increment

In this study, compatible height and diameter increment models were fitted for lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.), trembling aspen ( Populus tremuloides Michx.), and white spruce ( Picea glauca (Moench) Voss), using the relationship between diameter and height growth. It was assumed that tree diameter increment is directly proportional to height increment, and the proportionality constant is a function of competition and site productivity. The results showed that the fit statistics are comparable with results of other studies, with adjusted R2 ranging from 30% to 50%. A validation test of the models, using independent permanent sample plots data, showed that the short-term predictions of the models for both pure and mixedwood stands are fairly unbiased. The models also gave reasonable average height growth and diameter growth trajectories for pure stands of the three species and also projected long-term mixedwood (aspen – white spruce mixture) volume growth dynamics reasonably well. The models also projected reasonably well (i) the effect of increasing initial stem density on average diameter and height, and (ii) the stand volume compared with an older version the Mixedwood Growth Model (ver. 2000A). It was concluded that explicitly linking tree height and diameter increment models does not only have a solid ecological basis, but it also results in a compatible prediction of tree growth and stand dynamics.

Temporal, spatial, and structural patterns of adult trembling aspen and white spruce mortality in Quebec's boreal forest

2004 ◽  
Vol 34 (2) ◽  
pp. 396-404 ◽  
Author(s):  
Dominic Senecal ◽  
Daniel Kneeshaw ◽  
Christian Messier
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Picea Glauca ◽  
White Spruce ◽  
Trembling Aspen ◽  
Structural Patterns ◽  
Dead Trees ◽  
Mortality Ratio ◽  
Spruce Mortality ◽  
Old Trees

Temporal, spatial, and structural patterns of adult trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) mortality were studied in intact 150-year-old stands in the southwestern boreal forest of Quebec. For both species, mortality decreases (number of dead trees/total number of trees) with distance from the lake edge until 100–150 m, from which point it slightly increases. Strong peaks in mortality were found for 40- to 60-year-old aspen mainly between 1974 and 1992. Such mortality in relatively young aspen is likely related to competition for light from the dominant canopy trees. Also, the recruitment of this young aspen cohort is presumably the result of a stand breakup that occurred when the initial aspen-dominated stand was between 90 and 110 years old. For spruce, strong peaks in mortality were found in 110- to 150-year-old trees and they occurred mainly after 1980. No clear explanation could be found for these peaks, but we suggest that they may be related to senescence or weakening of the trees following the last spruce budworm outbreak. Suppressed and codominant aspen had a much higher mortality ratio than spruce in the same height class, while more surprisingly, no difference in mortality rate was found between dominant trees of the two species. Most spruce trees were found as standing dead, which leads us to reject the hypothesis that windthrow is an important cause of mortality for spruce in our forests.

Seed and bud legacies interact with varying fire regimes to drive long-term dynamics of boreal forest communities

2005 ◽  
Vol 35 (11) ◽  
pp. 2765-2773 ◽  
Author(s):  
Eliot JB McIntire ◽  
Robin Duchesneau ◽  
JP (Hamish) Kimmins
Keyword(s):  
Forest Management ◽  
Boreal Forest ◽  
Populus Tremuloides ◽  
Natural Regeneration ◽  
Forest Succession ◽  
Lodgepole Pine ◽  
Forest Community ◽  
Trembling Aspen ◽  
High Severity

Sustainable forest management that employs the emulation of natural disturbance paradigm develops plans based on disturbance-driven forest succession. However, most research on forest succession has focused primarily on postdisturbance species change, often ignoring predisturbance legacies. We used the FORECAST ecosystem management model and a newly created natural regeneration submodel to examine the interaction of fire severity, fire frequency, and natural regeneration to produce multicycle dynamics of white spruce (Picea glauca (Moench) Voss), lodgepole pine (Pinus contorta Dougl. ex Loud.), and trembling aspen (Populus tremuloides Michx.) in a western Canadian boreal forest. We simulated 19 different scenarios in a factorial disturbance experiment of three severities and six frequencies and a no-disturbance scenario. Our simulations resulted in a wide diversity of boreal forest community types, including trembling aspen dominated mixedwoods with high-frequency (75 year), high-severity (100% mortality) fires, and nearly pure lodgepole pine stands at midfrequency (100–125 year) and high-severity fires. With the unvarying disturbance regimes we used, a variety of different but recurring temporal patterns emerged. We show that the loss of seed source legacies reinforces the disturbance-driven species dominance, demonstrating community inertia. This study provides a long-term perspective to boreal forest management that demonstrates the role of disturbance and legacies in long-term dynamics.

Investigating competitive interactions from spatial patterns of trees in multispecies boreal forests: the random mortality hypothesis revisited

2002 ◽  
Vol 80 (1) ◽  
pp. 93-100 ◽  
Author(s):  
L R Little
Keyword(s):  
Boreal Forest ◽  
Spatial Patterns ◽  
Populus Tremuloides ◽  
Boreal Forests ◽  
Pinus Banksiana ◽  
Plant Competition ◽  
Forest Tree ◽  
Jack Pine ◽  
Competitive Interactions ◽  
Trembling Aspen

Plant competition is expected to produce an overdispersed spatial pattern relative to the initial pattern of individuals. The spatial patterns of two boreal forest tree species, Populus tremuloides Michx. (trembling aspen) and Pinus banksiana Lamb. (jack pine), were examined for evidence of intraspecific and interspecific competition. Data consisting of species, position, and age of tree stems were obtained from a 21-year-old, 40 m × 30 m postfire area of boreal forest in northern Alberta, Canada. Tree stems were mapped and classified according to size (greater or less than 5 cm in diameter at ground height) and species. A variation on the random mortality hypothesis was used to detect overdispersed patterns indicative of competitive interactions. This was done by comparing the size of neighbouring stems with those expected when the size or "success" of a stem occurred randomly. The results showed roughly two scales of pattern. First, large seed-regenerating jack pine neighboured each other more often than expected, but jack pine and trembling aspen neighboured each other less than expected. Second, although the large jack pine appeared to be clustered as neighbours, they tended to associate at distances farther than expected. These results show little evidence of density-dependence patterns in the species at the site, and the interspecific association between jack pine and trembling aspen could be indicative of a heterogeneous habitat.Key words: triangulation, size variability, Pinus banksiana, Populus tremuloides, jack pine, trembling aspen.

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