Determining stem biomass of Pinus massoniana L. through variations

Basic density is a key variable with which to express wood properties, but little attention has been paid to basic density traits in determining stem biomass. A total of 108 Pinus massoniana L. trees were selected from six sites in Hunan Province, China. Cross-sectional discs were cut for analysis using the stem analysis method. Results showed that the highest average basic density per stem for the six sites was 509.1 kg m23 and the lowest 448.9 kg m23. Basic density was significantly different (P, 0.05) among the sites. A significant effect of tree age on wood density was confirmed. Furthermore, the linear-mixed model was used to predict stem biomass. The allometric equation incorporating basic density at 10 % of tree height (Model 4) was compared with the equation using only diameter at breast height and tree height as independent variables. The mean stem biomass predicted by Model 4 (16.5 kg tree21) was not significantly different from the observed value (15.8 kg tree21). The results indicated that incorporating basic density as part of the independent variables could improve model fitness