关键词: 氮矿化速率, 丹江口库区, 土层, 覆膜土壤

Abstract: Three stand spatial structure parameters, including mingling degree, uniform angle and size ratio, were used to analyze species compositions and spatial structure patterns of a rare species Kmeria septentrionalis community in Mulun Reserve, Guangxi. The result showed that the community included 95 woody species, belonging to 55 families, 82 genera, being a typical unevenaged mixed broadleaf forest. The community was dominated by small DBH individuals, and tree numbers decreased as DBH increased, presenting an inverse J shape distribution. In the community, a majority of trees were strongly mingled (with an average mingling degree 0.742), and the size ratio was 0.508. Trees with hierarchical DBHs were evenly distributed in spatial structure, and most trees were of random to uneven distribution (with an average uniform angle 0.549), representing a mild aggregation. K. septentrionalis’ DBH structure also presented an inverse J shape, with decreased individuals in the process from seedlings to young trees. K. septentrionalis population had high mingling degree (0.796), moderate size ratio (0.400) and weak aggregated distribution (uniform angle 0.528). In sum, efficient conservation and appropriate human interference efforts are needed for a sustainable K. septentrionalis population.

Key words: soil layer, Danjiangkou Reservoir area., nitrogen mineralization rate, mulching soil