Soil Carbon Dynamics in a Mixed Deciduous Forest Following Clear‐Cutting with and without Residue Removal

Abstract

AbstractThe effect of two harvest intensities on soil carbon dynamics was determined for the first year following harvest of a mixed deciduous forest in Tennessee. Harvest procedures were clear‐cutting (all trees of all diameters cut) with only sawlogs removed (RL) and clear‐cutting with removal of all woody material except stumps (RR). There were no detectable differences in soil carbon pools between treated and control watersheds before harvest or 5 months after harvest. During the winter months immediately following harvest, CO2 efflux rates from the soil surface were greater in the intensively harvested watersheds than in the other watersheds. However, CO2 efflux rates were greater in the control watershed than in the harvested watersheds during the first growing season following harvest. This was apparently due to greater live root respiration in the control watershed because mineral soil respiration only (as determined by laboratory incubations) was greater in harvested watersheds than the control reflecting the higher soil temperature and moisture in the harvested watersheds. Annual soil respiration rates, predicted from laboratory measurements and field temperatures, were 92, 121, and 154 g CO2/m2 in the control watershed, RL watersheds, and RR watersheds, respectively. When extrapolated to a land area equal to that represented by the annual harvest of U.S. deciduous forests these rate increases amount to only ca. 0.006% of the annual carbon released from fossil fuel burning.