| Tropical forests play an important role in the global carbon cycling. Obtaining information of their carbon storage is an essential way to understand their function mechanism in carbon cycling. Monsoon rain forest over limestone is one of primary tropical forest vegetation types in Xishuangbanna, SW China. Acquainting its carbon storage data is useful to understand the carbon sequestration process in this region.In order to understand the carbon storage and its allocation of this vegetation types,four permanent plots (50 m×50 m) of monsoon rain forest over limestone were established in different sites. The grid method (10 m×10 m) was used to record all individuals with DBH greater than 2.0 cm in each plot. Shrub and herb species were investigated in nine 5 m×5 m and 2 m×2 m sub-quadrates respectively. The methods of allometric dimension analysis and sampling plots harvest were used to estimated the biomass of tree layer and shrub and herbaceous layer, respectively. Through the sampling tree data, Regression models with the form W=aDb was used to estimate the tree biomass, where W stands for the biomass of a species (kilograms for leaves, branches, stems or roots); a and b are constants; D stands for the DBH (cm). And the biomass of shrubs (ten 25 m2 quadrats), herbs (ten 1 m2 quadrats), dead wood (the whole plot), fallen tree debris (nine 100 m2 quadrats), large fallen branches (nine 25 m2 quadrats), litterfall (ten 1 m2 quadrats) was sampled in above different quadrats in four plots. Analyses of carbon concentration were performed by the Biogeochemical Laboratory in XTBG. The following aspects were included in this research: 1) Biomass in Monsoon rain forest over limestone; 2) The carbon concentration of plant and soil; 3) Carbon storage in the living plants and its distribution in different layers and organs; 4) Distribution of carbon storage in different DBH classes, species of tree layer; 5) Carbon storage in the litterfall and coarse woody debris; 6) Soil carbon storage and its distribution pattern; 7) Total carbon storage in Monsoon rain forest over limestone and its distribution pattern.The main results are as follwing:1) The biomass of monsoon rain forest over limestone in Xishuangbanna included all of live and dead plant materials was 361.588±100.635 t·hm-2 (95 % confidence interval, n = 4). Living biomass made up 97.42 % of the total biomass, coarse woody debris and litterfall hold the residue. Most living biomass (97.28 % ) of the monsoon rain forest over limestone was concentrated in the tree layer. And the biomass of living plant organs decreased in this order: stems > roots > branches > leaves.2) The carbon concentration changes insignificantly in the different plants samples. Carbon concentration reduced in this sequence: tree layer > shrub layer > herbs. Soil carbon concentration decreased with soil depths. The decreasing rate of soil concentration was intensive between 0 50 cm soil layers, and then gradually slows down.3) Carbon storage of the stem contributed 63.83 % of tree layers in monsoon rain forest over limestone, the most among all organs,and following was root and branch, carbon storage of the leaf was the lowest, which only contributed 1.58 % of tree layers.4) The carbon storage allocation among different DBH classes of tree layer concentrated on the middle DBH class and the largest one, which together accounted for 85.92 %. The most important species, in terms of carbon storage, made up a majority of total carbon storage of the tree layer. The carbon storage of ranked the first ten tree species accounted for 90.26 % of total carbon storage of tree layer.5) Most of the total carbon storage was concentrated in the tree layer, which was 155.420±48.853 t·hm-2. Carbon storage of shrub layer,herbaceous layer,woody lianas was 0.515±0.168 t·hm-2,0.236±0.168 t·hm-2,3.098±0.561 t·hm-2, respectively.6) The carbon storage of dead plant in monsoon rain forest over limestone was 4.171±1.323 t·hm-2, The carbon storage of litterfall was 1.657±0.582 t·hm-2, which contributed 39.74% of dead plant. And its amount of different components was in this order: leaves > twigs > Miscellaneous litters > flowers & fruits. The carbon storage of coarse woody debris was 2.514±1.325 t·hm-2, which contributed 60.26 % of dead plant. And its amount of different components was in this sequence: Standing dead trees > Fallen dead trees > Large dead branches.7) The soil carbon storage was 46.564±25.414 t·hm-2. The surface layer held the highest carbon storage, and the carbon storage decreased with depth. The upper layers (0 50 cm ) accounted for 86.00 % of the total soil carbon storage. Below 50 cm, the carbon storage of soil change was relatively stable.8) The total carbon storage of monsoon rain forest over limestone was estimated to be 210.005±58.126 t·hm-2, living plants accounted for 64.79 % 90.03 % , with an average of 75.84 %. And soil accounted for 7.04 % 32.90 % , with an average of 22.17 %. The dead plant contributed only 1.99 % of total carbon storage. The amount of carbon storage in monsoon rain forest over limestone was in this sequence: living plant > soil > coarse woody debris > litterfall.
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