<正>以乔木层树种重要值为指标，Pearson相关系数为测度距离，运用sPSs软件对双峰山国家森林公园人工林类型进行聚类划分。并分析了各群落物种多样性特征。根据聚类结果，按优势种命名原则，将双峰山森林群落划分为马尾松群落、杉木群落和柳杉+杉木群落，其中杉木群落物种多样性水平相对较高；乔木层、灌木层和草本层3个层次的物种多样性水平呈现出灌木层较高，草本层次之，乔木层较低的变化规律。但总体上，这些群落植物种类较少。物种多样性水平尤其是乔木层物种多样性水平低，应采用人工间伐、引入观赏价值高的乡土花卉及树种等方式促进群落物种多样性水平的提高，同时丰富森林景观。

Rational management density was one of the key techniques to realize directive breeding of poplar and brich natural forests, which help to improve the stability and economic benefit of forests. In order to discuss the effects of different management density on the growth, fixed sample plots were set up respectively with the different density under the dif ferent stand types and site conditions. The characters (height, diameter, volume and etc), form quality index, utility rate of luminous energy, nutrient and the moisture change of the soil were observed continuously. On the base of site classification of poplar and brich natural forests, we analyzed quantitatively the effects of different management density on utility rate of luminous energy, content of nutrition return, content of containing water of woodland soil, growth of the forest as well as the effect of timber quantity. The result showed that the management density obviously affected the growth of forests, accumulating of dry matter, litter fall decomposing, and the improvement of soil structure. The individual leaf content reduced along with the management density increasing. The total area of individual leaf and average crown of stand were maximal in the medium management density. The decomposing rate of litter fall decreased along with the density increasing. The returns of nutritive element were the most in medium management density. The moisture content of different depth soil reduced along with the depth deepening in the same density. The moisture reduced along with the density descending in the same depth. The annual growth of diameter of unit area increased along with the density descending of the polar and brich forests. The stand accumulation was the most in the medium management density.