东北落叶松和南方马尾松地下生物量模型研建

Establishment of below-ground biomass equations for larch in northeastern and Masson pine in southern China

在国家级森林资源监测中增加森林生物量估计已成为必然趋势,而地下生物量是森林生物量的重要组成部分。以东北落叶松和南方马尾松地下生物量数据为例,对地下生物量模型的两种常用建模方案进行对比分析,指出了存在的弊端,并提出通过利用度量误差模型,建立相容性地上、地下生物量模型和根茎比模型的方法。结果表明:利用度量误差模型方法,能有效解决一套数据、两种结果的问题,确保各个模型估计结果的协调一致性和参数的稳健性;在地下生物量实测样本只是地上生物量实测样本的子样本时,合适的做法是利用子样本建立根茎比模型,再结合利用大样本建立的地上生物量模型来联合估计地下生物量;林木根茎比的大小主要与直径相关,并随林木直径的增大而逐渐增加。本文所建立的两个树种的地下生物量模型的预估精度,南方马尾松可达到90%以上,东北落叶松可达到85%以上,能用于大尺度范围的森林生物量估计。

It has become a trend to supplement national forest resources monitoring with forest biomass estimation. The below-ground biomass is an important component of forest biomass. Based on the belowground biomass data of larch （Larix spp. ） in northeastern China and that of Masson pine （Pinus massoniana） in southern China, two approaches commonly used for modeling below-ground biomass, i. e. , below-ground biomass and root-shoot ratio equations, were compared, and problems in modeling below-ground biomass were addressed. Then, an approach to establish compatible above- and below- ground biomass equations and root-shoot ratio equation was proposed using the error-in-variable modeling method. The results show that ： 1 ） the new approach can be used to solve the problem of ＂one dataset, two results＂, and the estimation results using different equations are consistent and stable; 2） in case of no enough sample trees to be selected for measurement of below-ground biomass, a root-shoot ratio equation should be developed to estimate below-ground biomass with the aid of an above-ground biomass equation established through a large sample size; 3） the root-shoot ratio of an individual tree depends mainly on the diameter of the tree, and increases gradually with the growing diameter. The prediction preclslons of single-tree below-biomass equations developed in this study are 〉 85% for larch in northeastern China and 〉 90% for the Masson pine in southern China, and can be applied for estimating forest biomass at a large scale.