Abstract: By using lightfelling experiment and measuring carbon fluxes, the effects of lightfelling on the carbon budget of a midterm Korean pine forests restored by planting conifer and reserving broadleaved trees were investigated in Changbai Mountains of China. The results showed that both highintensity lightfelling and clearcutting significantly decreased CO₂ effluxes of soil respiration, autotrophic respiration, and heterotrophic respiration by 34.1%-39.2%, 37.2%-42.4% and 31.5%-37.3% (P<0.05), respectively in the growing season, while the low and moderateintensity lightfelling had no significant effects. Low and moderateintensity lightfelling and clearcutting had no significant effects on the net primary productivity and net carbon sequestration from the Korean pine forest (P>0.05), however, highintensity lightfelling significantly decreased the net primary productivity and net carbon sequestration by 24.7% and 27.0%, respectively (P<0.05). Compared to the uncut stands, highintensity lightfelling and clearcutting significantly decreased carbon emissions by 41.5% and 84.1%, respectively (P<0.05), while low and moderateintensity lightfelling had no influences on carbon emissions. Therefore, the highintensity lightfelling and clearcutting should be taken for the midterm Korean pine forests restored by planting conifer and reserving broadleaved trees, in order to maintain forest carbon sinks and accelerate their recovery to climax forests.

Key words: Yihe basin, landscape index, driving factors, landscape pattern