Abstract: Based on the inventory data of a 28-years-old Mytilaria laosensis plantation and the biomass measurements of the mean sample trees,the correlation between diameter at breast height (DBH),tree height(H),D²H and different parts of an individual tree were analyzed.Five biomass models,including power function model of individual tree of Mytilaria laosensis in southwest of Guangxi province were established by regression analysis.The results showed that the relationships between stem,branch,bark,total biomass and D²H were significant while the relationships between leaf biomass and DBH and between root biomass and H were significant.In the models in which the independent variable is the DBH (D),tree height (H) and D²H respectively,total tree,trunk,and bark biomass recession models were fitted best,leaf and root biomass recession models were fitted moderately,and branch biomass recession model were fitted worst.Power function model was the best regression model for fitting biomass of the most parts of an individual tree except bark biomass.

Key words: biomass, regression models, Mytilaria laosensis, southwest of Guangxi