Grant: Canadian Forest Service Research Partnership

The development of ecosystem management practices is required to maintain the ecological integrity of our managed forest ecosystems. This requires a good knowledge of the natural dynamics of our forest, its natural disturbance regime, and a comparison of the effects of natural vs. human-induced disturbances on its structure, function and composition. This project focuses on developing ecosystem management practices at the stand-level for a southern boreal mixewood. This forest type has complex dynamics due a diverse species mix and a large variety of natural disturbances.  Our general objective is to evaluate the extent to which partial cutting generates stand attributes similar to natural sub-catastrophic disturbances in this region and to what extent partial harvesting scenarios are socially acceptable. Our approach integrates three degrees of temporal perception - past, present and future - and three complementary methodological approaches (retrospective studies, silvicultural trials and stand dynamics modelling) to compare two broad types of secondary disturbances, specifically spruce budworm outbreaks and windthrow events (natural) with partial harvesting (industrial). Stands that have been affected by either of these disturbances between 1960 and 1980 will be inventoried and compared for composition, standing and fallen structures (live and dead), growth response to disturbance and recruitment. Parallel to this study, silvicultural trials have been established to compare the effects of different partial cutting treatments (retention, diameter limit, gap cuts) and soil surface-layer disturbances on stand composition, structure and seedling recruitment. Finally, data from both the retrospective and silvicultural trial components of this project will be used in the tree-level model SORTIE for comparisons of simulated future stand responses to both natural and industrial disturbances. The different scenarios will then be evaluated by a number of local interest groups (foresters, environmentalists and non-timber uses). The project will provide a framework upon which innovative silvicultural and management practices will be developed for this forest region.