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

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.

Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1181
Author(s):  
Guy R. Larocque ◽  
F. Wayne Bell

Environmental concerns and economic pressures on forest ecosystems have led to the development of sustainable forest management practices. As a consequence, forest managers must evaluate the long-term effects of their management decisions on potential forest successional pathways. As changes in forest ecosystems occur very slowly, simulation models are logical and efficient tools to predict the patterns of forest growth and succession. However, as models are an imperfect representation of reality, it is desirable to evaluate them with historical long-term forest data. Using remeasured tree and stand data from three data sets from two ecoregions in northern Ontario, the succession gap model ZELIG-CFS was evaluated for mixed boreal forests composed of black spruce (Picea mariana [Mill.] B.S.P.), balsam fir (Abies balsamea [L.] Mill.), jack pine (Pinus banksiana L.), white spruce (Picea glauca [Moench] Voss), trembling aspen (Populus tremuloides Michx.), white birch (Betula papyrifera Marsh.), northern white cedar (Thuja occidentalis L.), American larch (Larix laricina [Du Roi] K. Koch), and balsam poplar (Populus balsamefera L.). The comparison of observed and predicted basal areas and stand densities indicated that ZELIG-CFS predicted the dynamics of most species consistently for periods varying between 5 and 57 simulation years. The patterns of forest succession observed in this study support gap phase dynamics at the plot scale and shade-tolerance complementarity hypotheses at the regional scale.


2010 ◽  
Vol 40 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Xavier Cavard ◽  
Yves Bergeron ◽  
Han Y.H. Chen ◽  
David Paré

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.


2015 ◽  
Vol 166 (3) ◽  
pp. 159-167 ◽  
Author(s):  
Raphael Schwitter ◽  
Arthur Sandri ◽  
Peter Bebi ◽  
Thomas Wohlgemuth ◽  
Peter Brang

Lessons from Vivian for mountain forests – regarding the next storm The winter storm “Vivian” in February 1990 took Swiss forestry by surprise due to its enormous extent. It gave cause for entirely new and challenging questions for scientists and practitioners. Twenty-four years after the storm, the Swiss mountain forest tending group assessed in the frame of two workshops forest succession and the evolution of the protective effect against natural hazards in several well-documented Vivian storm areas at elevations between 1,500 and 1,700 m a.s.l. in the cantons of St. Gallen and Grisons. The decision to salvage the damaged timber or to leave it in place depends primarily on how the risk of bark beetle infestations is assessed. Lying stems can transiently reduce the risk created by natural hazards and favor stand establishment, by reducing snow movements and by serving as nurse logs in the long term. On several areas among those studied, forest succession has progressed so far that the protective effect is nearly restored. However, in the majority of the areas, this is not yet the case even 24 years after the storm. The presence of regeneration in the pre-storm stand, so-called advance regeneration, considerably accelerates forest succession in a windthrow area. If advance regeneration is absent, planting can considerably fasten succession in comparison to natural regeneration, which establishes often slowly. In summary, it is concluded that on large windthrow areas at high elevation the potential of natural regeneration is limited and that a more varied combination of the different treatment options should be envisaged in the case of future windthrow events.


2009 ◽  
Vol 85 (4) ◽  
pp. 631-638 ◽  
Author(s):  
Alison D Lennie ◽  
Simon M Landhäusser ◽  
Victor J Lieffers ◽  
Derek Sidders

Trembling aspen regeneration was studied in 2 types of partial harvest systems designed to harvest mature aspen but protect immature spruce and encourage natural aspen regeneration. Two partial harvest systems, where the residual aspen was either left in strips or was dispersed uniformly, were compared to traditional clearcuts. After the first and second year since harvest, aspen sucker density and growth was similar between the 2 partial harvests, but was much lower than in the clearcuts. However, in the partial cuts the regeneration density was very much dependent on the location relative to residual trees. The density of regeneration was inversely related to the basal area of residual aspen; however, sucker height was inversely related to the basal area of the residual spruce. Although there were adequate numbers of suckers after partial harvest, their viability and contribution to the long-term productivity of these mixedwood stands is not clear. Key words: silvicultural systems, forest management, residual canopy, white spruce, Populus tremuloides, Picea glauca, traffic


2012 ◽  
Vol 243 ◽  
pp. 123-132 ◽  
Author(s):  
Kenneth A. Anyomi ◽  
Frédéric Raulier ◽  
Daniel Mailly ◽  
Martin P. Girardin ◽  
Yves Bergeron

2015 ◽  
Vol 45 (5) ◽  
pp. 567-578 ◽  
Author(s):  
Louis Imbeau ◽  
Martin-Hugues St-Laurent ◽  
Lothar Marzell ◽  
Vincent Brodeur

Long-term exploitation of boreal ecosystems often results in a reduced range of ecological conditions that threatens several species. In most boreal jurisdictions, the northern extent of commercial forestry corresponds to economical rather than ecological considerations. Our general objective is to offer guidance for sustainable boreal forest management by using a biodiversity criterion based on three indicators. The first two indicators are part of a coarse filter referring to the proportion and fragmentation of tall, dense forest habitats, whereas a third one uses a fine filter for specific requirements of boreal caribou. We applied the methodology with and without anthropogenic disturbances on 1114 land districts to contrast the preindustrial potential and current capacity of Quebec’s boreal forest to support forest management. Originally, 826 districts (74%) were above the 20% cutoff value for the minimum proportion of tall, dense forest habitats. Among the 567 districts currently under forest management, 45 did not reach this value because of past anthropogenic disturbances. Originally, 88% of the districts had sufficient undisturbed habitats to maintain caribou populations, but anthropogenic disturbances reduced this proportion to 51%. The proposed methodology could contribute to delineating areas where sustainable forest management can be implemented. Our results also clearly show that management targets of the last decades were insufficient to prevent loss of habitats below strict minimum ecological thresholds. Our approach offers a general framework that could be adapted to other forested regions to attain similar biodiversity conservation objectives.


2005 ◽  
Vol 35 (11) ◽  
pp. 2679-2684 ◽  
Author(s):  
Tara L Keyser ◽  
Frederick W Smith ◽  
Wayne D Shepperd

Trembling aspen (Populus tremuloides Michx.) regeneration dynamics including sprout production, growth, and clone size were measured to determine the effects of fire on small aspen clone persistence following a mixed-severity wildfire in the Black Hills, South Dakota. Four years postfire, 10 small, isolated aspen clones per low and high fire severity classes were compared with 10 unburned clones. Regardless of severity, fire did not cause an increase in the area occupied by individual aspen clones. Clones affected by high severity fire had the greatest suckering response producing an average of 31 930 sprouts·ha–1; more than double the sprout density in unburned clones and 67% greater than the sprout density in clones affected by low severity fire. Sprout growth in high severity clones was 135% and 60% greater than sprout growth in unburned and low severity clones. The succession of these clones to more shade-tolerant ponderosa pine was delayed in clones affected by high severity fire as high severity fire caused significant pine mortality within and surrounding the clone, whereas, without further disturbance, pine encroachment and dominance will likely continue in clones affected by low severity fire.


The Condor ◽  
2000 ◽  
Vol 102 (4) ◽  
pp. 759-769 ◽  
Author(s):  
Keith A. Hobson ◽  
Erin Bayne

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.


1999 ◽  
Vol 29 (3) ◽  
pp. 393-397 ◽  
Author(s):  
C E Prescott ◽  
R Kabzems ◽  
L M Zabek

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.


Sign in / Sign up

Export Citation Format

Share Document