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

从树木衰老到其融入森林地面，粗木质残体（CWD）-各种腐烂状态的障碍物和原木-是许多复杂生态过程和功能的核心。人们充分认识到某些森林做法、枯木数量和质量的减少以及森林多样性的丧失之间的关系。该研究计划涵盖了CWD动态（招聘，分解，森林地板内的积累）和生态功能（固碳，森林营养，真菌多样性，森林再生）的几个方面的混合木材北方森林，其中物种与对比的自生态学以及木材特性和养分需求共存，并取代对方干扰和演替发生。此外，北方森林的森林地面是酸性和真菌占主导地位的环境，具有对比鲜明的有机物质池，其中来自富含C的凋落物（新鲜有机物质）的C的菌丝体转运允许真菌以营养丰富但碳贫乏的基质（例如森林地面的腐殖化层）为食。在接下来的五年里，我们将调查是否大量输入新鲜的木质残体，如那些由收获，可以促进分解的碳有限，但营养丰富的老池？这一假设将通过在加拿大北方盾牌混交林区的杜帕奎特湖研究和教学森林的自然林分和管理林分中进行的研究以及通过在实验室使用微观世界进行的补充研究来检验。三名研究生将参与这项研究。这些研究将对枯木可能影响自然森林生态系统中有机物质和养分的矿化和保留的速度、时间和程度的过程以及部分采伐在多大程度上确保管理林分中这些关系的连续性提供新的认识。

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.