Abstract: Based on the forest resource inventory data,according to the relationship model between sub-compartment volume and forest biomass,the forest biomass of 301 Forest Farm in Miyaluo forest region of west Sichun province was estimated.The forest biomass under each age class was analyzed,as well as the biomass of different forest type.The results indicated that the total biomass of the studied area was 3 041 229t,the average biomass was 87.13t/hm²,which is less than the average value of biomass both in national and Sichuan provincial level. This is mainly caused by poor quality of the site in which the main dominant species(Picea balfouriana and Abies squamata) are located,and caused by the low biomass value. The age structure of main forest type is irrational and the biomass from mature and over mature forest accounts for 69%.Among different forest types,the soil and water conservation forest occupied 80% of the total biomass.This study provided scientific basis for the forest resources management in the studied area.

Key words: west Sichuan, Miyaluo, biomass, age structure