Abstract: Currently, Beijing Songshan Nature Reserve possesses the only one natural Chinese pine forest in North China. We investigated 8 different aged natural Chinese pine forests in the reserve and used RDA analysis and variance decomposition to explore the effect of environmental factors on biomass allocation pattern in organs. Results indicated that biomass of tree layer increased with the increased stand age, and the biomass values of 40, 55, 70 and 95yearold forests were 116.96, 132.31, 144.86, and 170.82 t·hm^-2, respectively. The biomass of various organs (roots, leaves, bole wood, branches) also increased with the increase of stand age, but no significant difference in biomass allocation ratio of each organ existed among the forests with different ages (P>0.05). Stand age showed a significant positive linear correlation with organ biomass in tree layer. The two main components of environmental factors together accounted for 96.79%, 46.04%, and 86.80% of the variance of biomass distribution pattern in tree layer, shrub layer, and herb layer, respectively. The independent effect of the soil factor model was much greater than that of the terrain model in interpretation of the variance of tree layer and herb layer’s biomass allocation pattern, while the terrain factor model showed a greater independent role in explaining the variance of shrub biomass allocation pattern than the soil factor model.

Key words: Bacillus, corn straw, lignocellulose, biodegradation.