Carbon storage and fi xation, oxygen release of Pinus armandii plantations in middle Yunnan plateau, China

Biomass, carbon storage and spatial distribution characteristics, carbon fixation and oxygen release of the 16-year-old, 26-year-old and 43-year-old Pinus armandii plantations in Mopanshan Mountain in Yuxi, middle Yunnan plateau, southwest China were studied by adopting quadrat method and harvest method, and synthetically using photosynthesis equation, carbon tax and artificial oxygen method. The results are as follows: the biomass values of the three kinds of P. armandii plantations were 181.515 t·hm-2, 284.679 t·hm-2 and 295.311 t·hm-2, their total of carbon storage were 85.7513 t·hm-2,139.9344 t·hm-2,and 132.5 086 t·hm-2, their net carbon storages were: 5.3653 t·hm-2·a-1, 5.3836 t·hm-2·a-1 and 3.0827 t·hm-2·a-1; The carbon storage values in three kinds of forest age communities about various forest stories ranked from large to small order as this: carbon storage in arborous layer litter layer shrub layer herb layer, Carbon storages in arborous layer of three kinds of forest age accounted for 91.594%, 94.760% and 93.838% respectively; the variation coefficients of different forest age in the same organs(root, bark, leaf, stem, branch) were in the interval of 2.10% ~ 7.33%, while those of same forest age in different organs were in the interval of 2.12% ~ 5.82%; The variance analysis showed that apart from the arborous trees of the mature forest, and two other forest's arborous trees showed significant differences between nutritive organs; The middle-aged forest, near mature forest, mature forest of P. armandii plantations assimilated CO2 in the atmosphere, and desorbed O2, the value quantity of the assimilation CO2 and emancipation O2 were 355 044.221 3 yuan·hm-2, 216 003.386 1 yuan·hm-2 and 556 831.529 6 yuan·hm-2, and 338 767.648 4 yuan·hm-2、577 627.367 6 yuan·hm-2和 351 419.513 0 yuan·hm-2, respectively.