用分段建模方法建立东北落叶松立木材积和生物量方程

以东北落叶松(Larix spp.)立木材积和地上生物量数据为例,通过采用误差变量联立方程组和分段建模方法,研究建立了相容的立木材积方程、地上生物量方程及生物量转换函数.结果表明:采用误差变量联立方程组能确保立木材积与地上生物量之间估计结果的相容性,而分段建模方法能有效解决常用模型在小径阶存在的系统偏估问题;本文所建立的分段一元模型,地上生物量和立木材积的总体预估误差均不超过5％;分段二元模型,地上生物量的预估误差基本在4％以内,立木材积的预估误差则小于3％.

Using Segmented Modeling Approach to Construct Tree Volume and Biomass Equations for Larch in Northeastern China

Based on the tree volume and above-ground biomass data of larch (Larix spp.) in northeastern China, the compatible tree volume and above-ground biomass equations and biomass conversion functions were constructed using the error-in-variable simultaneous equations and segmented modeling approach. The results show that: (i) The error-in-variable simultaneous equations can ensure the compatibility of tree volume and biomass estimates, and the segmented modeling approach can resolve the problem of systematically biased estimation in small diameter classes for commonly-used tree volume and biomass equations; (ii) Through the one variable-based segmented equations, both the mean prediction errors (MPEs) of tree volume and above-ground biomass estimates for the whole data are less than 5%; and through the two variables-based segmented equations, the MPE of tree biomass estimates is about 4%, and the MPEs of tree volume estimates is less than 3%.