Moisture and soil texture effects on soil CO 2 efflux components in southeastern mixed pine forests

Abstract

Monitoring soil CO 2 efflux rates and identifying controlling factors, such as forest composition or soil texture, can help guide forest management and will likely gain relevance as atmospheric CO 2 continues to increase. We examined soil CO 2 efflux and potential controlling factors in managed mixed pine forests in southwestern Georgia. Soil CO 2 efflux was monitored periodically in two stands that differed in soil texture in 2001 and 2002, and in six additional stands in 2003. We also monitored controlling factors: soil temperature, moisture, organic layer mass, and A layer depth. Soil moisture and CO 2 efflux varied with soil texture differences among the stands. As expected, soil temperature had a strong influence on soil CO 2 efflux. Soil moisture, organic layer mass, and A layer depth also were correlated with soil CO 2 efflux during periods of water stress, but these relationships differed with soil texture. Forest management activities can alter components of soil CO 2 efflux, including soil carbon pools, temperature, and moisture; understanding the underlying variation of these components and resultant CO 2 efflux over soil types can help guide management toward desired forest carbon balance trends in southeastern mixed pine forests.