缙云山常绿阔叶林粗木质残体储量及特征

【目的】实地调查缙云山常绿阔叶林粗木质残体(CWD)的储量和特征,分析其影响因素,为深入认识常绿阔叶林生态系统中与粗木质残体相关的物质循环等关键生态过程提供理论依据,并为全球碳汇及相关学科的研究提供基础数据。【方法】以缙云山常绿阔叶林内已建立的2块0.5 hm^2样地为对象,调查并分析样地CWD的储量、类型组成、分解等级、径级分布格局以及地形对CWD储量的影响。【结果】缙云山常绿阔叶林CWD储量为38.42 t·hm^-2,其中倒木、枯立木、大枯枝和木桩储量分别为27.70,4.91,2.91和2.90 t·hm^-2,倒木是CWD的主要组成部分; CWD的树种组成与群落优势树种的组成相似,栲占CWD总量的88.44%;从径级分布来看,直径>35 cm的倒木和枯立木是CWD的主体; CWD主要处于分解中后期,中级分解和高级分解CWD的比例分别为63.20%和23.01%;地形对CWD的分布具有显著影响,坡面和山脊CWD储量高于沟谷(P<0.01)。【结论】缙云山常绿阔叶林CWD储量较大,处于该类森林系统的前列; CWD主要以处于分解中后期的优势种大径级倒木和枯立木为主,并主要分布在坡面和沟谷。在森林管理中应降低对CWD的人为干扰和去除,维持森林中枯立木、倒木、大枯枝和树桩等组分的自然状态。

Storage and Structural Characteristics of Coarse Woody Debris in an Evergreen Broadleaved Forest in Jinyun Mountain

【Objective】 By investigating the storage and structural characteristics of the coarse woody debris(CWD) in a subtropical evergreen broad-leaved forest in Jinyun Mountain, this study aims to promote the understanding of the material cycling process of woody debris in evergreen broad-leaved forests, and to provide fundamental data for global carbon sequestration related studies.【Method】 In two permanent monitoring plots(with a total area of 1 hm2), we quantified the storage of CWD and checked the proportion of CWD by varying size classes, types and decay classes. In addition, we looked into the differences in the storage of CWD at different topographic positions to learn how topography affect the spatial distribution of CWD.【Result】 The total storage of CWD on Jinyun Mountain was 38.42 t·hm-2, among which logs, snags, branches and stumps totaled 27.70, 4.91,2.91 and 2.90 t·hm-2, respectively. The species composition of CWD was similar to that of the above-ground forest community. Castanopsis fargesii was the dominant tree of the forest community, and it also made up 88.44% of the CWD. Logs and snags(>35 cm diameter-class) were the major components of CWD, and a majority of the CWD was found in the medium(63.20%) and late(23.01%) decay classes. Topographic position had a significant effect on the accumulation of CWD; the storage of CWD on the slopes and in the valleys were larger than the CWD storage on the ridges.【Conclusion】 The storage of CWD in Jinyun Mountain was at a high level when compared to the existing cases of the evergreen broad-leaved forests elsewhere. CWD is mainly dominated by medium-and late-decay, and large-sized C. fargesii snags and logs. It was mainly distributed on the slopes and in the valleys. Human disturbances and removal of CWD should be controlled in Jinyun Mountain to retain a combination of trees, snags, and logs within forests for sustainable forest management.