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

Abstract

Quantitative relationships between stand indices and carbon dioxide (CO<sub>2</sub>) 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 CO<sub>2</sub> 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-K<sub>2</sub>CrO<sub>7</sub> 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<sup>–1</sup> and 116.24 t·ha<sup>–1</sup>, respectively. The study revealed that the total amount of CO<sub>2</sub> stocks in the studied forest is 331.87 t·ha<sup>–1</sup>. One-way ANOVA with LSD test showed that CO<sub>2</sub> stocks varied significantly (P < 0.05) between the tree growth stages. There was a significant variation in CO<sub>2</sub> 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 CO<sub>2</sub> 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.