Effects of forest regeneration practices on the flux of soil CO₂ after clear-cutting in subtropical China

Reforestation after clear-cutting is used to facilitate rapid establishment of new stands. However, reforestation may cause additional soil disturbance by affecting soil temperature and moisture, thus potentially influencing soil respiration. Our aim was to compare the effects of different reforestation methods on soil CO₂ flux after clear-cutting in a Chinese fir plantation in subtropical China: uncut (UC), clear-cut followed by coppicing regeneration without soil preparation (CC), clear-cut followed by coppicing regeneration and reforestation with soil preparation, tending in pits and replanting (CCR_P), and clear-cut followed by coppicing regeneration and reforestation with overall soil preparation, tending and replanting (CCR_O). Clear-cutting significantly increased the mean soil temperature and decreased the mean soil moisture. Compared to UC, CO₂ fluxes were 19.19, 37.49 and 55.93 mg m^-2 h^-1 higher in CC, CCR_P and CCR_O, respectively (P < 0.05). Differences in CO₂ fluxes were mainly attributed to changes in soil temperature, litter mass and the mixing of organic matter with mineral soil. The results suggest that, when compared to coppicing regeneration, reforestation practices result in additional CO₂ released, and that regarding the CO₂ emissions, soil preparation and tending in pits is a better choice than overall soil preparation and tending.