ABSTRACT. This case study from northeastern Alberta, Canada, demonstrates a fundamentally different approach to forest management in which stakeholders balance conservation and economic objectives by weighing current management options from the point of view of their long-term effects on the forest. ALCES®, a landscape-scale simulation model, is used to quantify the effects of the current regulatory framework and typical industrial practices on a suite of ecological and economic indicators over the next 100 yr. These simulations suggest that, if current practices continue, the combined activities of the energy and forestry industries in our 59,000 km 2 study area will cause the density of edge of human origin to increase from 1.8 km/km 2 to a maximum of 8.0 km/km 2 . We also predict that older age classes of merchantable forest stands will be largely eliminated from the landscape, habitat availability for woodland caribou will decline from 43 to 6%, and there will be a progressive shortfall in the supply of softwood timber beginning in approximately 60 yr. Additional simulations involving a suite of "best practices" demonstrate that substantial improvements in ecological outcome measures could be achieved through alternative management scenarios while still maintaining a sustainable flow of economic benefits. We discuss the merits of our proposed approach to land use planning and apply it to the Western Canadian Sedimentary Basin.

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Birds and vegetation were surveyed in young, mature, and old aspen-dominated boreal forests in Alberta. Height and size of live trees, density of large dead trees, and volume of downed woody material increased during succession, whereas density of live trees decreased. Canopy heterogeneity had a bimodal relationship with succession: old forests had the highest, mature forests the lowest, and young forests an intermediate canopy heterogeneity. Old forests had greater bird species richness than young forests, which in turn had greater richness than mature forests. Twenty-seven, 3, and 10 bird species had their highest abundances in old, mature, and young forests, respectively. Seven bird species that nest and forage in canopy gaps and three bird species that nest and forage in large trees and snags were more abundant in young and old forests than in mature forests. Contrary to our predictions, patterns of richness and abundance for bird species that nest and forage in the canopy or in tree cavities were similar to those for bird species that nest or forage in the lower strata. Bird species preferring coniferous forests tended to be more abundant in old than in young or mature aspen-dominated forests, possibly because old aspen forests had more conifers than younger aspen forests.

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This study examines the densities, physical structure, and origins of snags and downed woody material (DWM) in young (20–30 yr), mature (50–65 yr), and old stands (120+ yr) in aspen‐dominated (Populus tremuloides Michx.) boreal forests of northeastern Alberta. Nearest neighbor and line intercept techniques were used to sample trees, snags, and DWM. Overall snag densities (≥10 cm diameter at breast height) were greater in mature and old stands. Overall coarse DWM (≥11 cm diameter) counts were greater in young and old stands; volume of coarse DWM was greater in old stands. Analysis of spatial components of variation suggested that fires produced initially heterogeneous patterns in the densities of trees and dead woody material. The degree of spatial heterogeneity within and among stands decreased as stands developed to maturity. As a stand developed from maturity to old age, densities of trees and dead woody material retained spatial homogeneity within stands; however, they became more heterogeneous among stands. Comparisons of size distributions and decay patterns indicated that in young stands approximately (X¯ ± 1 se) 19.1 ± 13.0 snags/ha (53.9%) and 48.5 ± 11.9 m3/ha of coarse DWM (79.2%) were derived from the prefire cohort of trees. Mature stands had 3.8 ± 4.0 snags/ha (5.8%) prefire snags. However, 50.4 ± 6.4 m3/ha coarse DWM were classified as prefire in origin (65.7%). In old stands, snags and coarse DWM were probably generated from the postfire cohort of trees. In general, the diversity of sizes and decay patterns of snags and DWM within stands was largely due to the mix of prefire materials and the postfire materials generated by self‐thinning and senescence/death of large trees. To simulate some of the conditions that occur after natural disturbances such as wildfires, timber harvest strategies should, in part, attempt to maintain the biological legacy associated with deadwood materials.