不同林分密度下川北白云山地区喜树人工林的群落结构和物种多样性

Effects of Stand Density on Community Structure and Species Diversity of Camptotheca acuminata Plantation in Baiyun Mountain,Mianzhu District,Sichuan Province

采用典型抽样方法,以四川绵竹白云山喜树人工林为对象,设置高密度、低密度样地各4块,分析喜树人工林的群落结构(物种组成及重要值、径级结构和高度级结构)和多样性水平(丰富度指数D值、Shannon-wienner指数H值、Simpson指数H'值和Pielou均匀度指数Jsw值)随林分密度的变化规律。结果表明:(1)在高密度下,径级结构和高度级结构均呈偏峰型;在低密度下,径级结构和高度级结构均呈山峰型。(2)高、低密度下喜树人工林乔木层的各物种多样性指数均较低,林下植被对密度变化的响应不同,高密度下的草木层多样性较高,低密度下的灌木层多样性较高。

By a field experiment, we studied the effects of different densities （ low density and high density） on community structure （species composition and important value, diameter class and height class） and species diversity（ The richness index S, Shannoil-wienner index H, Simpson index H＇, and Pielou index J,w of Camptotheca acuminata plantation in Baiyun Mountain, Mianzhu District, Sichuan Province）. Diameter class and height class had the same response to different density. Partial peak attribution was demonstrated in stand with big density, and peak attribution was demonstrated in stand with small density. In the tree layer of C. acuminata plantation, each species diversity indexes were low in both high and low density. Underground plants showed different responses to stand density, and there were higher species diversity of the herb layer under shrub layer in high and low density, respectively.