采用Ｎｅｌｄｅｒ环形设计原理进行田间试验设计，应用定性和定量相结合的分析方法，通过对欧美杨密度试验林定株连续测定材料的分析，揭示了密度作用的有关特性。结果表明，对于林木个体，密度作用具有非均衡性，其影响程度顺序为：冠幅＞胸径＞材积＞树高；对于林分，密度作用可使林分平均胸径降低，林木分化程度减弱；密度作用是一个随林龄、林地空间等因素而变化的动态过程，作用效应具有持续积累性，但其连年作用程度却有随年龄增加而降低并趋于稳定的趋势 The field experiments were designed based on Nelder’s ring design principle. The qualitative and quantitative analysis methods were used to analyze the density-dependent characteristics of the continuous determination of Populus euchromaucoides Lamb. The results showed that there was an imbalanced effect on the density of individual trees, and the order of influence was: crown width> diameter at breast height> timber volume> height of tree. For the stand, the average DBH of the stands decreased, the degree of differentiation of trees decreased, The effect is a dynamic process that varies with factors such as the age of the forest and the space of the forest land. The effect has a continuous accumulation, but its degree of successive years has the tendency of decreasing and becoming stable with increasing age