华北落叶松人工林密度对林木生长因子影响的研究

目的]为调控塞罕坝机械林场的林分密度提供参考。方法]选择林龄39年、立地条件相似的5种林分密度(225、500、600、700和800株/hm2)下的华北落叶松人工林为研究对象,采用标准地调查法,研究人工林密度对林木各生长因子的影响。结果]在225~800株/hm2的密度范围内,随着林分密度的增大,林木直径、冠幅、冠径比和单株材积逐渐降低,高径比和林分蓄积量逐渐增大,树高变化不明显。综合考虑林木生长因子的长势和林地生产力,当林木经营密度为500~600株/hm2时,各生长因子长势较好,林分蓄积量较大。结论]塞罕坝机械林场华北落叶松人工林的合理经营密度为500~600株/hm2。

Study on the Effects of Plantation Density of Larix principis-rupprechii on Forest Growth Factors

Objective] The study was to provide reference for regulating the forest density in Saihanba mechanical forest farm.Method] 39-year-old Larix principis-rupprechii plantations with similar stand condition and 5 forest densities of(225,500,600,700 and 800 plants/hm2) were taken as tested objects and the effect of plantation density on forest growth factors was studied by the method of sample plot investigation.Result] In the density range of 225-800 plants/hm2,the tree diameter,crown width,ratio of crown to diameter and individual volume were gradually decreased with the increasing of forest density.The ratio of height to diameter and forest stand volume was increased gradually,but the change of tree height was not obvious.Comprehensively considering the growth vigor of growth factors and the plantation productivity,the growth vigor of growth factors was better and the forest stand volume was bigger when the management density of forest was 500-600 plants/hm2.Conclusion] The reasonable management density of L.principis-rupprechii plantation in Saihanba mechanical forest farm was 500-600 plants/hm2.