广西主要树种立木生物量模型的研建

摘要

在广西境内收集杉木、马尾松、桉树、硬阔类、软阔类等树种333株，按收获法进行生物量测定，分别树种采用W＝c1×Dc2，W＝c1×（D2 H）c2，W＝c1×D c2×Hc3模型进行地上部分生物量拟合，并采用加权回归估计消除模型的异方差，利用部分有根部生物量测定的样本，分别树种建立地下与地上生物量回归模型，获得平均根茎比参数。结果表明：1）采用W＝c1×Dc2×Hc3结构建立地上生物量模型，具有较高的精度；2）通过加权回归后，地上生物量模型精度略有降低，但模型稳定性增强；3）主要树种地上生物量模型的决定系数R2均达到0.93以上，总相对误差（TRE）和平均系统误差（MSE）均控制在±1％以内，平均预估精度基本在94％以上，结合平均根茎比参数，可在一定径级范围内用于广西主要树种生物量估测。%A total of 333 trees from China fir,masson pine,eucalyptus,Hard broad-leaf and soft broad-leaved species growing in Guangxi province were collected and their biomass was measured by harvest method.Three equations,W=c1 ×Dc2 ,W=c1 ×(D2 H)×c2 and W=c1 ×Dc2 ×Hc3 ,were applied to a-bove-ground biomass (AGB)fitting of each tree-species group,and the heteroscedasticity of equations was eliminated by weighted-regression.Roots biomass of some tree samples were employed to model the e-quations of root-to-shoot ratios.The results showed that:(1 )the precision of AGB model based on W=c1 ×Dc2 ×Hc3 was higher;(2 )weighted regression slightly decreased the precision of AGB equations,but enhanced the stability of equations;(3 )determination coefficients of AGB equations were greater than 0.9 ,and the total relative error (TRE)and mean systematic error (MSE)were basically controlled with-in ± 1%,then the estimate precision of biomass equations was about 94%.Therefore,combing with the equations of root-to-shoot ratios,these above-ground biomass equations were suitable to estimate the bio-mass of the major tree species of Guangxi in a certain range of diameter at breast height (DBH)class.