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

点击翻译按钮获取中文摘要

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.