Biomass harvests in boreal forests: minimizing environmental impacts and maximizing benefits

点击翻译按钮获取中文摘要

Biomass harvesting for biofuels has become an important activity for Canada's forestry economy. However, it remains uncertain how biomass harvesting and forest renewal can best maintain and support biodiversity and ecosystem functions while maintaining site productivity and promoting stand regeneration. In addition, there is lack of tools that can be used to measure the environmental costs and benefits of different management strategies in terms of their impacts on biodiversity and ecosystem functions. Focusing on central boreal forests, we will address how biomass harvesting, compared with conventional stem-only harvesting and wildfire, affect site productivity, biomass production, and carbon storage, soil greenhouse gas fluxes, stand albedo, and biodiversity,; and will examine tradeoffs among economic and ecological objectives. We will test the hypotheses that: (i) biomass harvesting may compromise site productivity, stand regeneration, biomass production, carbon storage, soil GHG fluxes, and biodiversity in comparison with alternatives; (ii) forest renewal that promote revegetation after disturbance can mitigate the potentially negative effects of biomass harvesting, and alternatively, negative impacts may be compounded without forest renewal; (iii) ecosystems may show nonlinear responses to land-use intensification, and thus management options with limited or no ecological losses that still satisfy economic gains may be identified at the operational level. We will focus our efforts on two dominant forest types: jack pine ecosystems on coarse and medium sandy soils and mixedwoods of trembling aspen and spruce on mesic soils in the central region. A mechanistic understanding of the interactions between resource use and silvicultural treatments with stand development and the tradeoffs between economic benefits, ecological functions, and biodiversity in boreal forests will allow us to make recommendations for the forest sector on how to design management regimes that minimize negative ecological impacts while maintaining site productivity and promoting stand regeneration.