中国森林生物量的估算:对Fang等Science一文(Science,2001,291:2320～2322)的若干说明

ESTIMATING BIOMASS CARBON OF CHINA'S FORESTS: SUPPLEMENTARY NOTES ON REPORT PUBLISHED IN SCIENCE (291: 2320-2322) BY FANG et al. (2001)

Science杂志于 2 0 0 1年发表了方精云等人关于中国森林植被碳库及其变化的论文 (Fangetal.,2 0 0 1,2 91:2 32 0～ 2 32 2 )。该文利用大量的生物量实测数据 ,结合使用中国 5 0年来的森林资源清查资料及相关的统计资料 ,基于生物量换算因子连续函数法 ,研究了中国森林植被碳库及其时空变化。这是一个大时空尺度的工作 ,涉及一些大尺度生态学研究的原理、方法以及尺度转换问题。由于篇幅所限 ,论文并未详细说明这些问题。为了帮助理解大尺度生态学研究的方法和思路 ,本文给出了论文中涉及生物量计算的理论基础 ,对数据和计算方法等也进行了较为详细的说明。生物量换算因子的连续变化、区域森林生物量的计算方法以及由样地实测到区域推算的尺度转换构成该项研究的 3个主要的理论基础 ,其中换算因子的连续变化是关键。

Science magazine has published a paper by Fang et al. (2001, 291: 2320-2322) which, based on the variable BEF (Biomass Expansion Factor) method, discusses forest biomass carbon and its changes in China in the past 50 years, by using direct field measurements and forest inventory database. This is a large spatio-temporal scale study, associated with principles and methods for a large-scale ecology study and scaling-up. Due to a limited space, the Science paper does not describe these in details. In order to help understand methodologies for such a large-scale study, here we presented the basis for calculating regional biomass in details, and described the data sources and methodologies used in the Science paper. The variable BEF changes, calculation equations of regional forest biomass and scaling up from direct biomass measurement to regional biomass estimation are three main foundations for estimating China's forest biomass carbon in the Science paper. Among these, the first one is the most critical to calculation of biomass carbon.