Biomass and carbon stocks in Schima superba dominated subtropical forests of eastern China

Quantitative relationships between stand indices and carbon dioxide (CO2) stocking are missing in the evergreen broadleaved forests (EBLFs) in eastern China and this hinders to estimate carbon (C) budget in the subtropical region. We determined the vegetation-soil C pool and CO2 stocking using stand indices [diameter at breast height (DBH), total height (H) and wood density] in Schima superba dominated EBLFs in the Tiantong National Forest Park in eastern China. Vegetation biomass was determined by a non-destructive method using the tree volume and wood density approach while soil C concentration was determined using the oil bath-K2CrO7 titration method. Finally, multiple regression and one-way ANOVA with LSD test were used for data analysis. Results showed that total C stocks in the vegetation and the 0-20 cm surface soil were 90.53 t.ha-1 and 116.24 t.ha-1, respectively. The study revealed that the total amount of CO2 stocks in the studied forest is 331.87 t.ha-1. One-way ANOVA with LSD test showed that CO2 stocks varied significantly (P < 0.05) between the tree growth stages. There was a significant variation in CO2 stocking capacity within sapling and pole growth stages but no significant variation within standard stage. The stepwise multiple regression analysis showed that DBH, BA and H were related to the C stocking while wood density had no significant effect. The significant amount of C stocking in EBLFs in the Tiantong National Forest Park of eastern China showed the potential and significant C stocks by trees. As the C pool structure changes due to a change in the forest type and location, therefore this study is important to estimate C stocks and predict CO2 stocks from stand indices in EBLFs which serve as a scientific basis for sustainable forestry operations, rational utilization of forest resources and global warming reduction in EBLFs in subtropical regions of China.