Abstract: Aiming at the problem that the tree height measurement is difficult and inaccurate,based on large sample field measurement data about biomass for Larix in northeast China,the biomass model on DBH(diameter at breast height)and the biomass model based on DBH and total height were fitted respectively.Then taking a large sum of DBH and height data from larger region as independent variables,effects of model form and region on prediction for aboveground biomass of Larix were studied.The results showed that no significant difference in predicted biomass was found between the model on DBH and the model based on DBH and height at province and large region levels in the region,where the sample trees for fitted biomass equations were sampled.While in the other region,there was a significant difference between the model on DBH and the model based on DBH and height at province and large region levels,the prediction from the model on DBH was more than that from the model based on DBH and height in all diameter classes.In all region with prediction samples,the prediction biomass from the model on DBH was more than that from the model based on DBH and height at smaller diameter classes,this should be paid attention to when fitting biomass equations.

Key words: Larix, biomass, model, region