A Basin-Scale Estimation of Carbon Stocks of a Forest Ecosystem Characterized by Spatial Distribution and Contributive Features in the Liuxihe River Basin of Pearl River Delta

Forest ecosystems make a greater contribution to carbon (C) stocks than any other terrestrial ecosystem. To understand the role of regional forest ecosystems in global climate change and carbon exchange, forest C stocks and their spatial distribution within the small (2300 km2) Liuxihe River basin in China were analyzed to determine the different contributors to the C stocks. Forest C stocks were quantified by measuring the biomass of trees, understory vegetation, litter and roots, as well as soil organic C, using data from field samples and laboratory experiments. The results showed that forests stored 38.04 Tg·C in the entire basin, with secondary and planted forests accounting for 89.82% and 10.18%, respectively, of the stored C. Five types of forests, a subtropical evergreen broad-leaved forest, a subtropical coniferous and broad-leaved mixed forest, a subtropical coniferous forest, a timber forest, and a non-wood forest, stored 257.55 ± 15.01, 218.92 ± 9.59, 195.24 ± 18.29, 177.42 ± 17.55, and 117.86 ± 6.04 Mg·C·ha−1, respectively. In the forest ecosystem C stocks of the basin, soils on average contributed about 73.78%, not including root underground biomass. The results of this study, which provide baseline forest C stock data for ecosystem services and regional C flux research, are useful to support the basin-scale forest management and land use change.