Soil CO2 efflux in clear-cut and uncut red pine (Pinus densiflora S. et Z.) stands in Korea

This study was carried out to determine the effects of clear-cutting on soil CO2 efflux in a 42-year-old pine (Pinus densiflora S. et. Z.) stand. The variation of soil CO2 efflux rates with soil temperature, soil pH, soil moisture and soil organic carbon (C) content was measured monthly for 1 year in two pine plots; a clear-cut pine (CCP) and an uncut pine (UCP) plots. Mean soil CO2 efflux rates during the study period were significantly higher (P < 0.05) in CCP (0.52 g CO2 m−2 h−1) than in UCP (0.37 g CO2 m−2 h−1). High soil CO2 efflux rates in CCP were attributed to the change of soil temperature, soil pH, soil organic C and soil moisture content following canopy removal. In addition, soil temperature in CCP was significantly higher (1–3 °C) than in UCP except during winter (P < 0.05). Soil pH was also significantly higher (0.1–0.5 units) in CCP than in UCP (P < 0.05), suggesting a better environment for microbial or root growth activity. In contrast to soil temperature or soil pH, soil organic C and soil moisture content were significantly lower in CCP than in UCP (P < 0.05). The results indicated that the increased soil CO2 efflux rates in CCP compared with UCP could be due to the combined effect of high soil temperature, high soil pH, low soil organic C and soil moisture content.