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天敌在松毛虫种群动态中起重要作用，但把天敌的作用加入系统管理模型中却很困难。本文试图用林分因子代替天敌的作用，因为林分条件可以方便地用于系统模型中。通过对浙江省衢县、常山县和龙游县不同立地条件的222块样地的调查数据的分析，从70多科的昆虫群落中选择了16个关键种（科），并对林分因子和各样地关键种的种数、个体数、多样性之间的关系进行了典型相关分析。结果表明郁闭度和植被条件（灌木层盖度、灌木层高度、草木层盖度、草木层高度、总盖度）是刻划昆虫群落功能的关键林分因子。根据郁闭度的变化和植被条件用系统聚类方法可以把林区分为四种类型，这四种类型林地的昆虫多样性指数、种数、个体数量和松毛虫的密度都存在明显差异；在每种林地都建立了松毛虫密度的变化率与关键林分因子间的回归模型，所有的回归的相关系数都相当高（0．924－0．964），因此可以认为对林地的分类是合理的，而且用林分因子评估天敌的影响在实践中是可行的。
Natural enemies play an important role in the population dynamics of the pine caterpillars, but it is difficult to include the natural enemies in the system management model. This article attempts to use the stand factor instead of the natural enemy, because the stand conditions can be easily used in the system model. Based on the survey data of 222 plots of different site conditions in Qu County, Changshan County and Longyou County of Zhejiang Province, 16 key species (families) were selected from the insect communities of 70 families, and the stand factors And various types of key species, the number of individuals, the relationship between the typical canonical correlation analysis. The results showed that canopy density and vegetation conditions (shrub layer cover, shrub layer height, vegetation cover, grass layer height, total cover) were the key stand factors for the insect community function. According to the changes of canopy density and vegetation conditions, the forest area can be divided into four types by using systematic clustering method. There are significant differences in insect diversity index, species number, individual number and dendrolimus density among the four types of forest land. For each species of woodland, a regression model was established between the rate of change in dendrolimus density and the key stand factors, and the correlation coefficients for all the regressions were quite high (0.924-0.964), so the classification of forest land could be considered reasonable , And it is feasible in practice to assess the impact of natural enemies with stand factors.