Carbon accumulation and distribution were studied in three plots of a 13 years old Chinese fir （Cunninghamia lanceolata） forest in Daqingshan,Guangxi. The results showed that the average carbon concentration in all organs was in the following order: leaf （510.5）>bark （501.8）>wood （485.1）>root （476.5）>branch（462.1） （g·kg~ -1 ）. The carbon concentration of soil （to 60 cm depth） ranged from 11.4 to 21.1 （g·kg~ -1 ）,with an average of 16.6 （g·kg~ -1 ）. Carbon concentration of surface soil （to 20 cm） was higher than the other layer. The average carbon concentrations （g·kg~ -1 ） in different layers were in the order as: trees （497）> shrub （437.5） >standing litters （437.5）>herb （407.8）. The carbon storage of the forest ecosystem was in order of soil layer>vegetation >standing litter. Of total average carbon,23.87% was in vegetation component,74.27% in soil （60 cm depth）,and only 1.86% in standing ground litter layer. The tree layer occupied 22.93% of total carbon storage in the ecosystem and 96.07% of carbon storage in the vegetation layer. The carbon storage in different organs was positively related to the biomass of corresponding organs. Trunk accumulated the highest carbon storage,comprising 58.40% of carbon storage in tree layer. Secondly,root made up 20.09% of total tree carbon. The annual net productivity of Chinese fir plantation was 10.10 t·hm~ -2 a~ -1 ,stored carbon up to 4.67 t·hm~ -2 a~ -1 ,equal to 17.13 t·hm~ -2 a~ -1 of CO2. Chinese fir plantation was an important sink of atmospheric CO2. But its capacity of C sequestration decreased gradually in this region.
