云杉矮槲寄生与环境因子的主成分分析

The Principal Component Analysis of Environmental Factors of Arceuthobium sichuanense

云杉矮槲寄生是多年生半寄生性种子植物，近年来已成为严重危害青海省云杉林的主要灾害之一。本研究以青海省仙米林场受矮槲寄生侵染的云杉林为对象，通过标准样地调查了云杉矮槲寄生林间发病的影响因子，采用SPSS软件进行云杉矮槲寄生害病情指数与环境因子的主成分分析，结果表明，影响云杉矮槲寄生病情指数变化前5位的因子依次是林分郁闭度、草本生物量、海拔、pH值和坡度。郁闭度与病情指数呈负相关关系，在郁闭度大于0．7以上的天然林分中云杉矮槲寄生发生较轻或没有发生，而在郁闭度0．4～0．5之间，云杉矮槲寄生发生严重。研究结果将对云杉矮槲寄生害的防治提供理论依据。

Arceuthobium sichuanmse is a hemiparasite angiosperm, and it has been one of the major diseases whichare seriously threating the spruce forest in Qinghai province. By standard sampling survey, the impact factors ofthe forest infected by Arceuthobium sichuanmse was studied, and by using SPSS, the Principal Component Analysisof diseased indicators and environmental factor of Arceuthobium sichuanmse were conducted. The results shows thatthe top five factors which cause disease outbreak of Arceuthobium sichuanens are canopy density, herbaceous bio-mass, elevation, PH value and slope. The forest canopy density had a negative correlation with the incidence ofArceuthobium sichuanens. The incidence of Arceuthobium sichuanense is lower when the forest canopy density was over 0.7, while it will become serious when the forest canopy density was 0. 4 - 0. 5.