晋西土石山区森林次生演替过程中群落结构及复杂性

在晋西黄土高原中阳县土石山区阴坡地段，选择4种典型群落次生演替阶段样地,研究了森林次生演替过程中群落结构和群落复杂性的变化规律.结果表明，群落演替过程中，群落高度级结构及径级结构呈现明显的变化规律，高大个体在群落中所占比例逐渐增加，低高度级和小径级个体数量则呈先增加后减少的趋势.按高度级结构计算的群落树种组成复杂性H(X)、层次结构复杂性H(Y|X)、群落总体复杂性H(X,Y)均呈先增加后减小的趋势:H(X)指数值在演替初期阶段为2.96,演替中期增加到3.85,至乔木林阶段又降低为3.75;H(Y|X)指数值演替初期为1.27，演替中期增加为1.66，至乔木林阶段则为1.37.

Dynamics of forest community structure and complexity in the process of secondary succession in bedrock area of West Shanxi Province

In this paper,four plots representing the typical secondary succession stages of forest community were selected at the shady slope of bedrock area in Zhongyang County of West Shanxi,aimed to study the variation patterns of the structure and complexity of forest community in the process of secondary succession.The results showed that in the succession process of the community,there was an evident regularity in the variation of height and diameter class structure.The proportion of high and big individuals in the community increased gradually,while that of low and small ones increased first but decreased then.From the viewpoint of height class structure,the compositional complexity of tree species H(X),structural complexity of tree species H(Y|X),and complexity of whole community H(X,Y)all increased first,but decreased then with the succession.At the early,middle and arbor stages of succession,the H(X)value was 2.96,3.85 and 3.75,while H(Y|X)value was 1.27,1.66 and 1.37,respectively.