Soil CO 2 efflux in clear-cut and uncut red pine ( Pinus densiflora S. et Z.) stands in Korea

Abstract

This study was carried out to determine the effects of clear-cutting on soil CO 2 efflux in a 42-year-old pine ( Pinus densiflora S. et. Z.) stand. The variation of soil CO 2 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 CO 2 efflux rates during the study period were significantly higher ( P < 0.05) in CCP (0.52 g CO 2 m −2 h −1) than in UCP (0.37 g CO 2 m −2 h −1). High soil CO 2 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 CO 2 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.