Estimating biomass and net primary production from forest inventory data:: a case study of China's Larix forests

Forest inventory data (FID) are important resources for understanding the dynamics of forest biomass, net primary production (NPP) and carbon cycling at landscape and regional scales, especially for complying with the Kyoto Protocol on greenhouse gas reduction and validating ecosystem dynamic models from regional and global scales. FID-based biomass and NPP estimation models for China's Larix forests are discussed in this paper. The results indicated that the relationships between biomass (B) and its volume (V), NPP and mean annual biomass increment (B/A) or mean annual volume increment (V/A) can be expressed as hyperbola curves for both natural and planted Larix forests. The relationship between NPP and its biomass is not linear, which is not the same with the former studies. These FID-based models take into account the change in the ratio of forest biomass to volume with stand age and the effect of stand age on forest NPP. The result also indicates that natural and planted forests should be treated separately when biomass and NPP of forest are estimated based on FID. (C) 2002 Elsevier Science B.V. All rights reserved.