一个新的通用性相对生长生物量模型

针对West等(1997;1999)提出的理论生物量模型与经验模型存在显著差异的问题,对应用最广的一元生物量模型M=aDb的2个参数进行专题研究。首先,基于几何学的观点推导出参数b的理论值为7/3(≈2.33),与大量已有研究结果的对比表明,该理论参数值能够很好地描述地上生物量与胸径之间的平均相对生长关系;然后,利用包含1441株样木的5组立木生物量数据对新提出的通用性理论模型进行验证;最后,分析参数a与木材密度ρ之间的相关性,并建立二者之间的线性回归模型。新的模型既简单明了,又能反映不同树种之间的生物量差异,可为建立用于区域性和国家级森林生物量估计的通用性生物量模型提供可行途径。

A New General Biomass Allometric Model

To implement monitoring and assessment of national forest biomass, it is becoming the trend to develop generalized single-tree biomass models suitable for large scale forest biomass estimation. Considering that the theoretical biomass allometric model developed by West et al. (1997; 1999) was statistically different from the empirical one, the two parameters in the most commonly used biomass equation M=aDb were analyzed in this paper. Firstly, based on the ideas of geometry, the theoretical value of parameter b was deduced, i.e. , b=7/3(≈2.33), and the comparison with many empirical studies conducted throughout the globe indicated that the theoretical parameter could describe soundly the average allometric relationship between above-ground biomass M and D (diameter on breast height). Secondly, using 5 biomass datasets which consisted of 1 441 M-D pairs of sample trees, the new general biomass allometric model was validated. Finally, the relationship between parameter a and wood density ρ was analyzed, and the linear regression was developed. The new model, which is not only simple but also species-specific, offers a feasible approach on establishment of generalized biomass models for regional and national forest biomass estimation.