影响油松毛虫发生程度的生态地理因素分析

Analysis of the ecological geographic factors influencing the occurrence degree of Dendrolimus tabulaeformis Tsai et Liu

通过对80块样地的调查,运用主分量分析、逐步回归分析和通径分析的方法,研究了生态地理因素与油松毛虫发生程度之间的相互关系,结果表明,生态地理因素对油松毛虫发生程度的影响是综合作用的结果;林分因子与地形因子相比,林分因子对油松毛虫的影响较大;在14个生态地理因素中与油松毛虫发生程度关系紧密的关键性因素,按影响由大到小依次为:龄组﹥坡度﹥冠幅﹥轮枝数﹥林分密度﹥主林层郁闭度;且油松毛虫的发生程度与坡度、林分密度、冠幅、主林分郁闭度、冠幅和轮枝数呈负相关,与龄组呈正相关关系;各因素的直接作用均大于间接作用的影响。

Based on the survey at 80 sample plots, using principal components analysis, typi- cal regression analysis, and path analysis, this study researched the relationships between the ecological geographical factors and the occurrence degree of Dendrolimus tabulaeformis Tsai et Liu. The result showed a comprehensive effect of ecological geographic factors on the occurrence degree of Dendrolimus tabulaeformis Tsai et Liu. And the Stand factor is the close key factor to the occurrence degree of Dendrolimus tabulaeformis Tsai et Liu among the the 14 ecological geographic factors, with greater impact on Dendrolirnus tabulaeformis Tsai et Liu than the terrain factor at Age group〉Slope〉Crown〉Wheel branch number〉 Stand density〉Canopy density of main storey. The occurrence degree of Dendrolimus tabu- laeformis Tsai et Liu is negatively related with slope, stand density, crown, canopy density of main storey and wheel branch number but positively related to age group. The direct effect of various factors are larger than the indirect effect.