Carbon Storages and Densities of Different Ecosystems in Changzhou City, China: Subtropical Forests, Urban Green Spaces, and Wetlands

Climate change mitigation and carbon neutrality are current hot topics. Forests, urban green spaces, and wetland ecosystems are recognized as important carbon sinks. The Yangtze River Delta region in Eastern China, which plays a pivotal role in China's economic and social development, is rich in such carbon-sink resources. There is, however, a lack of regional carbon data. The investigation of carbon storage and carbon densities of forest, urban green space, and wetland ecosystems is, therefore, of great importance. In this study, the forest resource management map (including wetland) and green space system planning map of Changzhou city, combined with a field investigation and laboratory experimental analysis, were used to estimate the carbon storages and carbon densities of the forest, urban green space, and wetland ecosystems in Changzhou city. The average carbon density and carbon storage in Changzhou were 83.34 +/- 4.91 Mg C ha-1 and 11.30 +/- 0.67 Tg C, respectively, of which soil accounted for 74%, plants accounted for 25%, and litter accounted for less than 1%. The forest ecosystem contributed the most to the carbon pool (72%), with the green space ecosystem and the wetland ecosystem each accounting for 14% of the carbon pools. Clearly, the forest, green space, and wetland ecosystems in Changzhou city have a large carbon storage capacity. This study is of significance as it provides data on the carbon sink functions of forest, green space, and wetland ecosystems at the provincial and national regional scales.