栎树林分因子与栗山天牛危害程度的风险分析

摘要

研究了13个与栗山天牛危害程度有关的林分因子,并对这些林分因子与栗山天牛危害林地有虫株率进行逐步同归分析,从中筛选出林地坡位、栎树胸径和主林层郁闭度3个关键因子.结果表明:栗山天牛危害林地有虫株率(y)与坡位(x1)和胸径(x6)呈显著正相关关系,与主林层郁闭度(x4)呈显著负相关关系,依此建立多元回归模型:y=0.071 2+0.691 8x1 -0.507 4x4 +0.561 3x6,经检验,平均差异程度为0.174 2.因此,可用该模型对栗山天牛危害程度进行风险评估.%Thirteen stand description factors affecting the harm extent of Massicus raddei was studied, and by step-wise regression analysis, three key factors, slope position, DBH and crown density, were selected. The results showed that there was a significant negative correlation between the crown density and the ratio of infected oaks, and a significant positive correlation existed between the other two key factors and the ratio of infected oaks. Using these three key factors, a multiple regression model was established for risk analysis of the harm extent of Massicus raddei. The average difference degree was 0.174 2, so the model is suitable for risk assessment of the harm extent of the pest.