[Simulation of carbon stocks of forest ecosystems in Northeast China from 1981 to 2002].

Based on the forest carbon budget model for China FORCCHN, which had been improved through adding variables and modules of precipitation (rainfall and snowfall) intercepted by tree crown and of understory and litter, the spatiotemporal distribution pattern of carbon stocks of forest ecosystems in Northeast China from 1981 to 2002 were simulated. The results showed that from 1981 to 2002, the forest ecosystems in Northeast China played a role of carbon sink, and the total carbon stock was about 12.37 Pg C x a(-1), of which, the stock of vegetation and soil was 4.01 Pg C x a(-1) and 8.36 Pg C x a(-1), respectively. During the study period, the carbon stock of both vegetation and soil all had an increasing trend, and the increase of air temperature contributed more than the change of precipitation. Spatially, the carbon density of vegetation had the characteristics of high in southeast part and low in northwest part, with an average of 10.45 kg C x m(-2). Most of the forest ecosystems in Northeast China had a higher soil carbon density, with a mean value of 21.78 kg C x m(-2) and the maximum in part regions of Daxing'anling, Xiaoxing'anling, and Changbai mountains. The forest area in Northeast China accounted for 31.4% of that in the whole country, possessing an important position in China forest carbon pool. The carbon stock of vegetation and soil in the forests of Northeast China occupied 74.23% and 63.88%, and the carbon density of vegetation and soil was 2.70 and 1.22 times of that in the forests of the whole country, respectively.