Impacts of timber harvesting on soil physical properties in wetlands

Abstract

Six wet pine flat sites were salvage logged following Hurricane Hugo in the fall of 1989. High soil moisture conditions during salvage operations resulted in soil compaction and deep rutting (puddling) on primary skid trails. Two studies were established to assess the effects of trafficking on soil physical properties and hydrologic characteristics. One addressed soil compaction; the other addressed soil rutting (puddling). Each study consisted of 3 sites (blocks) and trafficked and undisturbed areas were sampled on each site. Effects of trafficking on soil physical properties and hydrology were tested by comparing the disturbed (trafficked) and undisturbed subplots.

Traffic increased bulk density and decreased soil porosity (macro-, micro-, total), water table levels, and saturated hydraulic conductivity within the compacted areas. However, the depth to reducing conditions was not significantly different from between undisturbed and disturbed areas of compacted sites.

Puddling increased in bulk density and a decrease water table levels, depth of reducing conditions, soil porosity (macro-, micro-, and total), and saturated hydraulic conductivity (field and laboratory methods). Soil strength was not significantly different between disturbed and undisturbed areas.

Overall, puddling resulted in soil changes that are more deleterious to tree growth than did compaction. Also puddling changes may prove more difficult to mitigate.