Soil Physical Changes Associated with Forest Harvesting Operations on an Organic Soil

Abstract

The influence of forest operations on forest soil and water continues to be an issue of concern in forest management. Research has focused on evaluating forest operation effects on numerous soil and water quality indicators. However, poorly drained forested watersheds with organic soil surface horizons have not been extensively investigated. A study was initiated in the Tidewater region of North Carolina to gain a better understanding of the impact of harvesting operations on poorly drained organic soils. Soils on the study site, having >80% organic matter (OM) content to a depth of 60 cm below the soil surface, were classified as shallow organic soils. Soil physical properties were examined by collecting soil cores from control and treatment watersheds in a nested design. Compaction caused by the harvest operation increased bulk density (D b ) from 0.22 to 0.27 g cm −3 , decreased saturated hydraulic conductivity ( k sat ) from 397 to 82 cm h −1 , and decreased the drained volume for a given water table depth. However, D b following the harvest remained low at 0.27 g cm −3 The drained volume at equilibrium following the lowering of the water table from the soil surface to a depth of 200 cm was reduced by 10% from that of control watershed as a result of harvesting.