Deadwood dynamics and functions in natural and managed forests: Can we have our cake and eat it too?

从树木衰老到融入森林地面，粗木质碎片(CWD)--处于不同腐烂状态的木质碎片和原木--是许多复杂生态过程和功能的核心。人们很好地认识到某些森林做法、枯木数量和质量的减少与森林多样性的丧失之间的关系。该研究计划涵盖北方混交林CWD动态(补充、分解、在森林地面中积累)和生态功能(固碳、森林营养、真菌多样性、森林更新)的几个方面，在混交林中，具有不同自生态以及木材特性和养分需求的物种共存，并在干扰和演替发生时相互替代。此外，北方森林的森林地面是一个以酸性和真菌为主的环境，具有不同的有机质池，在这种环境中，菌丝转移富碳凋落物(新鲜有机质)中的C，使真菌能够以营养丰富但碳贫乏的底物(例如森林地面的腐殖化层)为食。在接下来的五年里，我们将调查大量的新鲜木质垃圾的投入，例如那些由收获引起的垃圾，是否可以促进碳含量有限但营养丰富的老水池的分解？这一假设将通过在加拿大北部盾牌混交林地带的杜帕奎特湖研究和教学森林的天然林和管理林中进行的研究，以及通过在实验室使用微型宇宙进行的补充研究来验证。三名研究生将参与这项研究。这些研究将对枯木可能影响天然森林生态系统中有机质和养分的矿化和保持的速度、时间和数量的过程以及部分采伐在多大程度上确保这些关系在受管理的林分中的连续性提供新的线索。

From tree senescence to its incorporation into the forest floor, coarse woody debris (CWD) - snags and logs in various states of decay - is central to many complex ecological processes and functions. The relationships between certain forest practices, decreases in deadwood quantity and quality and the loss of forest diversity are well recognized. The research program covers several aspects of CWD dynamics (recruitment, decomposition, accumulation within the forest floor) and ecological functions (carbon sequestration, forest nutrition, fungi diversity, forest regeneration) of mixedwood boreal forests, where species with contrasting autoecology as well as wood characteristics and nutrient requirements coexist and replace each other as disturbances and succession take place. Moreover, forest floor of boreal forests is an acid and fungi- dominated environment with contrasting organic matter pools in which mycelial translocation of C from C-rich litter (fresh organic matter) allows fungi to feed on nutrient rich but carbon poor substrates (e.g. the humified layer of the forest floor). In the next five years, we will investigate whether large inputs of fresh woody debris, such as those caused by harvesting, can promote decomposition of C-limited but nutrient-rich older pools? This hypothesis will be tested through studies conducted in natural as well as managed stands of the Lake Duparquet Research and Teaching Forest in the mixedwood zone of the Canadian boreal shield and by means of a complementary study conducted in the laboratory using microcosms. Three graduate students will be involved in the research. The studies will shed new light on the processes through which deadwood may affect rate, timing and magnitude of mineralization and retention of organic matter and nutrients in natural forest ecosystems and the extent to which partial harvesting ensures the continuity of these relationships in managed stands.