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双条杉天牛是柏类园林树木的重要害虫之一。利用Taylor等10种方法,对双条杉天牛初期幼虫空间分布型的测定结果表明,双条杉天牛初期幼虫在林间属于聚集分布,分布的基本成分是个体群。由此得出了林间调查的理论抽样数公式,其抽样方式以Z字形取样方法最佳。在此研究基础上,对初期幼虫种群的资料代换方法进行了研究,在所采用的4种代换方法中,以平方根的代换方法最佳。
Double cedar is one of the major pests of cypress garden trees. Spatial distribution patterns of larvae of Cunninghamia lanceolata were determined by 10 methods (Taylor et al.). The results showed that the initial larvae of Crabgrass were clustered and distributed in the forest, and the basic components of the population were individuals. Thus, the theoretical formula of sampling number in forest survey is obtained, and the sampling method is the best way to sample in zigzag. On the basis of this study, the data substitution method of initial larval population was studied. Among the four substitution methods, the square root substitution method was the best.