Evaluation of Biomass and Carbon Stocks in Three Pine Forest Types in Karst Area of Southwestern China

Afforestation has been considered as a possible solution to mitigate climate change because forests sequestrate atmospheric CO2 and convert it into their woody biomass and soils. In the present study, stand biomass and carbon (C) stock were investigated in three pine forest types: Masson pine natural forests (MPNF), Masson pine plantation forests (MPPF), and Slash pine plantation forests (SPPF) in the karst area of southwestern China. The results showed the total forest ecosystem C, total stand C, and total overstory C storage was significantly higher in SPPF stands than in MPNF and MPPF stands. The overall total C stocks in SPPF stands (165.14 Mg C ha(-1)) was higher than that of MPNF (115.54 Mg C ha(-1)) and MPPF (141.77 Mg C ha(-1)). The majority of C storage was in soil pool of three types of forest stands, accounting for 54.2%, 49.6% and 46.7% in MPNF, MPPF, and SPPF stands, respectively. The variation in C stock in the different forest types was due to differences in tree species feature and stand densities. The results suggest the plantation forests had higher C stocks than native forests at the early growth stage in this specific karst area of northwestern China.