Abstract: Forest inventory data (FID) are an important resource for compiling accurate information of forest volume at landscape and regional scales, and are useful for understanding the dynamics of forest biomass, net primary production (NPP) and carbon cycling, especially in consideration of compliance with the Kyoto Protocol on greenhouse gas reduction. Field and literature data of Larix forests in China show that the relationships between biomass and volume, net production and net annual biomass increment or net annual volume increment could be expressed as hyperbolic curves for both natural and planted Larix forests. However, the relationship between net production and biomass was not clear. A set of new FID-based biomass models and net production models for both natural and planted Larix forest were developed. These models take into account the change in the ratio of forest biomass and volume with the stand age and the effect of stand age on forest NPP.