Dynamics of Net Production of Chinese Forest Vegetation Based on Forest Inventory Data

According to the net primary productivity data of 1?266 samples about different forest types in China,the functional relationship between biomass,volume,community growth and annual litter fall about Chinese major forest types were established and the net production and dynamic changes about Chinese forest ecosystems were studied by using the data from six NFIs of China from 1973 to 2003.The results showed that the net production of Chinese forest vegetation was 1?360.64×106t/a during the 6th NFI,and the average net primary productivity was 9.53 t/hm2.a.The net production was composed mainly of young and middle-age forests and had some differences between different regions with the net production higher in northeast and southwest,and lower in other regions.From 1973 to 2003,the net production of Chinese forest vegetation increased from 790.13×106t/a to 1?360.64×106t/a.The net production was the lowest before 1970s and then increased gradually.Whereas the average net primary productivity of Chinese forest vegetation was higher before 1970s and decreased until the end of 1990s and then increased again.