Abstract: By using LI-8100 CO₂ Flux Meter, the CO₂ flux of soil surface and the temperature and moisture content at soil depth of 10 cm in conifer/broadleaved mixed forests under different intensity of selective cutting in Dailing Forest Bureau of Heilongjiang Province were determined simultaneously from 2003 to 2007, with the changes of soil surface CO₂ flux after selective cutting and their affecting factors studied. The results showed that the CO₂ flux was correlated with soil temperature and moisture content, with a relatively high confidence ranged from 68% to 98%. Selective cutting increased the CO₂ flux, with an average annual increment being from 7.17% to 26.89%. There was a significant quadratic correlation between soil surface CO2 flux and cutting intensity (R²=0.961). Soil organic matter content and cutting intensity were the main factors affecting the changes of soil surface CO₂ flux after selective cutting.

Key words: ecosystem service value, main ecosystem service, dynamic evaluation, driving force