Abstract:

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=aD^b 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.

Key words: allometric model, biomass estimation, geometry, theoretical parameter, wood density