Carbon Storage in Young Chinese Fir (Cunninghamia lanceolata) Monoculture and Mixed Plantations in Subtropical China

Mixed plantations of Chinese fir (Cunninghamia lanceolata, CL) and five broadleaf tree species (Ailanthus altissima (AA), Betula luminifera (BL), Sapindus mukurossi (SM), Tciliata varpubescens (TV) and Zelkova schnideriana (ZS)) were established. After 5 years, spatial distributions of carbon stocks were studied in Chinese fir monoculture and mixed plantations. Overstory tree carbon storages were significantly lower (P<0.05) in mixed plantations than that in Chinese fir monoculture plantations. Understory vegetation carbon storages were significantly lower (P<0.05) in CL+BL and CL+ZS plantations than in the monoculture plantations. No significant difference was observed between other mixed plantations and monoculture plantations. Litter carbon storage was significantly lower in CL+ZS plantations than in the monoculture plantations (P<0.05), there was no significant difference between other mixed plantations and monoculture plantations. Soil carbon storages (0-60 cm) in mixed plantations were higher than that in the monoculture plantations, except for CL+SM plantations. Total ecosystem carbon storage was no significant difference between monoculture and mixed plantations, except for CL+SM plantations. Nevertheless, spatial distribution of carbon storage was different among these mixed plantations.