林分密度对华北落叶松人工林林下植被多样性影响的研究

以河北省塞罕坝机械林场为研究地点，采用标准地调查法，研究在立地条件一致的情况下林分密度对华北落叶松人工林林下植被多样性的影响，结果表明：在华北落叶松人工林林下植被各多样性指数中，灌木的Simpson指数D和草本植物的Shannon-Wiener指数H受林分密度的影响最大。林分密度对华北落叶松人工林林下植被的科、属组成以及物种丰富度、物种多样性、物种均匀度均有一定程度的影响，随着林分密度的增加它们均呈不同程度降低的趋势。

Research on the Effects of Stand Density on understory vegetation Diversity of Larix principis-rupprechii plantation

The study site was located in Saihanba mechanical forest farm of Hebei province, through the research on the effects of stand density on understory vegetation diversity of Larix principis-rupprechii plantation by using of sample plot investigation method, the result showed that the effects of stand density on Simpson index D of shrub and Shannon-Wiener index H of herb are biggest in each of the diversity index of understory vegetation of Larix principis-rupprechii plantation. There were a certain extent effects of stand density on families and genera compositions, species richness, species diversity, species evenness of understory vegetation of Larix principis-rupprechii plantation and they showed decreasing trend in different degree with increasing of stand density.