关键词: 油松人工林, 碳汇效应, 内蒙古农牧交错带

Abstract: Afforestation project plays an important role in ecosystem restoration and exerts significant influence on global carbon cycle. This study took the Pinus tabulaeformis man-made forests in the agro-pasture zigzag zone of Inner Mongolia as research target, and natural grasslands as a referance; analyzed the effects of “conversion from grazing land to forest” on carbon stock and carbon cycle in the ecosystem. The results indicated that afforestation activities had led to rapid increase of vegetation carbon stock. Along with the prolonging of forest age, a dynamic change occurred in slowly increase of litter carbon stock and ecosystem carbon stock, while soil carbon stock firstly dropped and then gradually rose. The average carbon sink rates changed with forest age as following: medium age forest > near-mature forest > young forest > mature forest. With mature forest (43 a) as reference, the vegetation layer carbon sequestration potential (CSP) was 3 695.28 g/m2, while the P. tabulaeformis ecosystem CSP was 4 384.99 g/m2. These results indicated that after conversion from grazing land into forest in the study area, the P. tabulaeformis ecosystem was a considerable carbon sink in the long term.

Key words: Pinus tabulaeformis man-made forest, carbon sink effect, agro-pasture zigzag zone in Inner Mongolia