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

生物燃料的生物量收获已成为加拿大林业经济的一项重要活动。然而，生物量收获和森林更新如何才能最好地维持和支持生物多样性和生态系统功能，同时保持立地生产力和促进林分再生，仍不确定。此外，缺乏可用于衡量不同管理战略对生物多样性和生态系统功能的影响的环境成本和效益的工具。以中部北方森林为重点，我们将讨论生物量收获，与传统的干只收获和野火相比，如何影响场地生产力，生物量生产和碳储存，土壤温室气体通量，林分生物量和生物多样性，并将研究经济和生态目标之间的权衡。我们将检验以下假设：（i）与替代方法相比，生物量采伐可能会损害立地生产力、林分再生、生物量生产、碳储存、土壤GHG通量和生物多样性;（ii）促进干扰后重新植被的森林更新可以减轻生物量采伐的潜在负面影响，或者，如果不进行森林更新，负面影响可能会加剧;（三）生态系统可能对土地使用的集约化表现出非线性反应，因此，可以在业务一级确定生态损失有限或没有生态损失但仍能满足经济收益的管理备选办法。我们将集中力量于两种主要的森林类型：中部地区粗粒和中粒桑迪土壤上的短叶松生态系统和中粒土上的颤白杨和云杉混交林。机械的理解之间的相互作用资源利用和造林的治疗与立场的发展和经济效益，生态功能和生物多样性之间的权衡，在寒带森林将使我们能够为林业部门提出建议，如何设计管理制度，尽量减少负面的生态影响，同时保持网站的生产力和促进林分再生。

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.