Abstract: In this paper, three methods including allometry with observed data (AMOD), allometry with calculated data (AMCD), and average sample tree determination(ASTD)were used to estimate the foliage biomass, branch biomass, trunk biomass, and to tal biomass of Pinus elliotii in Qianyanzhou station. The results showed tha t branch diameter was highly correlated to branch biomass and branch leaf biomass, and the linear equation with single parameter (d³) was the best type of equation to describe the correlation. The total biomass calculated by these three methods was adjacent, being 7.9×10⁴kg·hm^-2by AMOD, 8.0×10⁴kg·hm^-2 by AMCD, and 7.41×10⁴ kg·hm^-2 by ASTD. The foliage biomass , branch biomass and trunk biomass, especially the foliage biomass,had a distinct difference when estimated by the three methods, being >20% higher or lower by ASTD than by the other two methods. In related literatures, allometric equation s were also used to estimate the total biomass and apparatus biomass of P. elliotii, but the calculated values were all higher than those by the three methods. AMOD was most reliable when estimating forest biomass, while AMCD could take the place of AMOD in some extent.

Key words: Land use change, Terrestrial ecosystem, Carbon storage, Deforestation, Reforestation, Tillage, Rotation, Fertilization