Abstract: Taking the broad-leaved Korean pine forest area in Changbai Mountains, a typical eastern forest belt of Northeast China for global change as test object, and by using the approaches of trenching-plot and infrared gas exchange analyzer, this paper analyzed the soil respiration in a selected series of degraded Korean pine forest ecosystem, i.e., broad-leaved Korean pine forest (CK), poplarbirch forest (Y), hardwood forest (S), Mongolian oak forest (M), and bare land (L). In the growth season of the forests, soil respiration showed a clear single peak curve, with the maximum in July or August. The soil respiration decreased in the sequence of Y>M>CK>S>L. The amount of CO₂ release in Y and M was about 0.4 and 0.3 times higher than that in CK; and that in S and L accounted for 88% and 78% of CK, respectively.

Key words: Changbai Mountains, broad-leaved Korean pine forest, degraded forest ecosystem, soil respiration, biochar, Lou soil, soil water thermal properties, soil aggregate, mean weight diameters.