云蒙山典型森林群落垂直结构研究

Study on Vertical Structue of Forest Communities in Yunmengshan

采用以树冠光竞争高度为基础的林分垂直层数量化方法研究了云蒙山几种典型森林群落的垂直结构特征,并将不同群落的垂直层划分结果与树高系统聚类分析结果相比较,发现在森林群落垂直层划分过程中,树冠光竞争高度附近的树被误划的几率较高;截止系数a=0.4时,平均误划率最低,为10.10%。对几种森林群落结构指标相关性分析表明:森林群落垂直分层数与乔木高度多样性指数、树高变异系数及乔木物种多样性指数呈显著正相关;乔木高度多样性指数和树高变异系数与灌木层多样性指数呈极显著正相关,而与草本层多样性指数却均呈显著负相关。几种描述林分垂直结构的指标能很好地描述森林群落的垂直分层情况,同时森林群落的垂直结构对下层植物的物种组成具有重要影响。

A stratification method of forest vertical structure was built based on crown cut-off height point（CCHP） in stand. Compared to the result by systematic clustering of tree height in the stand, stratification by the new method was validated, during the process of stratification of stand, tree height near the CCHP was easy to be classified wrongly, and the best classification results came from the process with 0.4 of competition coefficient used, in which the average rate of mis-classified trees was 10. 10% in all nine plots. Besides the number of canopy layers（ Sn ） , several other indices related with vertical structure were also calculated, i. e. , Gini index （Gc ） , variants of tree heights （Cv） , and biodiversity index of tree layer（ Ht ） , shrub layer（ Hs ） and grass layer（ Hg ）. The correlation analysis between those indices showed that there were common correlation existed among them, which indicated that Sn, Gc, Cv could be used to describe the vertical structure of forest stand properly and the complexity of vertical structure could influence the development of shrub and grass layer.