TEMPORAL AND SPATIAL PATTERNS IN ABOVEGROUND BIOMASS WITHIN DIFFERENT HABITATS IN A SUB-TROPICAL FOREST

In order to explore the variation in aboveground biomass among five topographically-defined habitats in old-growth forest, we measured aboveground biomass within a 20 ha permanent plot in Southern China. Aboveground biomass was estimated by using allometric regression equations. In the present study, there was no significant difference between the average aboveground biomass in 2005 (153.7 +/- 58.7 mg ha(-1)) and in 2010 (152.3 +/- 60.8 mg ha(-1)). Biomass also varied substantially among habitats, from 138.9 Mg ha(-1) in the higher slope and lower valley habitat to 200.1 mg ha(-1) in the mountain ridge habitat in 2005, and from 132.1 mg ha(-1) in the lower slope to 198.8 mg ha(-1) in the mountain ridge in 2010. Medium trees were the largest contributor (48%) to the total aboveground biomass within all habitats. Variability in species contributions to total habitat biomass were suggestive of species habitat preferences. This study provides a detailed overview of aboveground biomass patterns among old-growth forest habitats and highlights the importance of incorporating community characteristics and environmental variables (i.e. topography) into forest ecosystem carbon studies. The results will further our understanding of the contributions of old-growth forests to global carbon cycles and provide valuable information to improve conservation planning strategies.