摘要
建立生物量模型是生物量估测的主要手段，而建立与材积兼容的生物量模型是实现生物量调查与森林蓄积量调查相结合的基础。因此，采用变量逐步筛选法建立了落叶松和椴树与材积兼容的生物量模型。模型的参数估计采用了加权最小二乘法，以消除异方差现象。同时，提出了５个指标用于模型评价，即参数变动系数Ｃｖｉ、总相对误差Ｅｒ、平均相对误差Ｅｍ，平均相对误差绝对值Ｅａ和预估精度Ｐ。研究结果表明，所建的生物量模型不仅实现了与材积表的兼容，而且估计效果和预估精度较以往的ＣＡＲ模型都有显著提高。
Establishing biomass models is a major way of biomass estimate.To establish biomass model compatible with volume table is the base of realizing the combination of forest biomass survey and growing stock invertory.Based on this point,the progressive variable selection method is used to establish biomass model compatible with volume table for Larix olgensis and Tilia amurensis ,and weighted least squares method is used to estimate parameters for clearing up phenomenon of non homogeneous variance.In the meantime,the paper presented five indices for evaluation of models,they are coefficient of variation for parameters C v i , total relative error E r , average relative error E m average absolute value of relative error E a and prediction precision P . All the results show that biomass models established in this paper not only realize compatibility with volume table,but also get remarkable improvement in estimate effect and prediction precision comparing with previous model CAR.According to the results,some reference models are given.
出处
《林业科学研究》
CSCD
北大核心
1999年第1期53-59,共7页
Forest Research
基金
林业部重点课题
