北京山区黑桦天然次生林不同种群的格局分析

根据2006年6月对北京八达岭林场0.5 hm2黑桦天然次生林样地的调查结果，采用点格局分析方法，对群落内主要种群和黑桦种群各龄级个体在不同尺度下的空间分布格局和相互关系进行了研究。结果表明:①黑桦和蒙椴种群单种格局在研究的空间尺度范围内呈显著的集群分布，元宝槭种群在小尺度上呈集群分布，在较大尺度上呈随机分布。②主要树种之间存在种间关联，重要值最高的黑桦和蒙椴呈显著负相关关系，说明此群落组成和结构不稳定，正处于植被演替阶段。③黑桦种群各龄级木的分布格局随树龄的增加，由集群分布逐渐趋向于随机分布。④黑桦种群相邻龄级木之间的相互关系主要是正相关关系，而不相邻龄级木之间的关系多为负相关关系。 

Pattern analysis of different populations in natural secondary forest of Betula davurica in mountainous area of Beijing

Based on the inventory results of 0.5 hm2 sample plot of Betula davurica natural secondary forest in Badaling Forest Farm of Beijing in June of 2006,the method of point pattern analysis was employed to study the spatial distribution patterns of tree populations and the relationship of main populations of community and individuals in different age classes of B.davurica under different scales.The results showed that:1)the distribution patterns of B.davurica population and Tilia mongolica population presented ...