CARBON STORAGE AND BUDGET OF MAJOR CHINESE FOREST TYPES

The regional characteristics of carbon storage and carbon dioxide fluxes of major Chinese forest ecosystems were studied from the points of internal biological cycle, based on published data regarding forest biomass, productivity, the organic carbon content of soil profile, stand and annual weight of the litter, soil respiration etc. The results are as follows: the average carbon density of Chinese forest ecosystem is 258. 83 t .hm-2, showing a generally increasing trend with increasing latitude; carbon density of the vegetation, soil and litter is 57. 07 t ·hm-2, 193. 55 t .hm-2, and 8. 21 t.hm-2, respectively ; the characteristics of the carbon density of these three fractions (vegetation, soil, lit-ter) were also analyzed ; from the recent areal data provided by the Ministry of Forestry of China in 1989-1993 the total carbon storage of Chinese forests was estimated to be 281. 16 X 108 t, in which the vegetation, soil and litter were 62. 00X 108 t, 210. 23 X 108 t, 8. 92 X 108 t, making up 22. 2%, 74. 6%, 3. 2%, respectively of the total, the carbon storage of deciduous broad-leaved forests, warmer temperate coniferous forests, evergreen / evergreen- deciduous broad-leaved forests, Picea-Abies forests, and Larix forests were the major carbon pool of the forest, making up 87 % of the total; in China the net flux between the forest ecosystem and the atmosphere is 4. 80 X 108 t .a-1, and the forest ecosystem acts as a carbon sink when exchanged with the atmosphere, absorbing 48. 7% of the carbon dioxide from burning of biomass, fossil fuel and human respiration (9. 87 X 108 t .a-1 ). Generally, the carbon dioxide fixing capacity of the deciduous forest is higher than the coniferous forests, decreasing with increasing latitude.