天山云杉粗木质残体生态功能的研究

Coarse woody debris is a massive and functionally important component of Tianshan Mountain forest ecosystems, both natural and managed. Decaying logs and snags provide habitat for many organisms and participate in biogeochemical element fluxes within the forest ecosystem. Because of its large mass and slow decay rates, it also plays a significant role in the global carbon cycle. For these reasons, it is important to understand the dynamics of coarse woody debris (CWD) in the forest ecosystem. In this research project, a five-class decay classification system of fallen wood involving characteristics of bark, twigs, wood surface, and log shape was developed for natural spruce forest stands in Tianshan Mountain. Meanwhile, the research estimated the volume and the biomass of CWD in Tianshan Mountain spruce forest. Mean CWD volume was 337.61m3/ha, and dry biomass was 87.98Mg /ha. Based on the woody debris density, a simple negative exponential function of time showed an average decomposition rate constant of 0.01174 per year. Decomposition time that the woody debris density decreased 50%, 90%, and 95% was approximately 59a, 196a, and 255a, respectively. The more significant is that the research got a new understanding about the role of fallen woods playing in the forest regeneration. That is, the most important ecological function of fallen wood playing in the forest regeneration is to overcome autoallelopathy or autotoxicity of Tianshan Mountain spruce. This new understanding has very important scientific significance for the theory of boreal forest disturbance and succession.

通过对天山云杉粗木质残体生物量动态、粗木质残体中营养物质的循环及粗木质残体对天山云杉天然更新作用的研究，阐明天山云杉粗木质残体在森林生态系统中的生态功能，它将对促进天山林区森林的恢复与生态系统可持续经营具有重要的理论价值和应用前景。