Long-term effects of commercial sawlog harvest on soil cation concentrations

There IS increasing concern about the effects of nutrient removal associated with various forest harvesting practices on long-term sate productivity. We measured exchangeable soil cation concentration responses to a commercial clearcut sawlog harvest in mixed hardwoods on a 59.ha watershed in the southern Appalachians. Soils were sampled 17 months prior to, and periodically for I7 years after, harvest. Concentrations of Ca, Mg, and K, increased significantly in the O-IO-cm soil layer for 3 years following harvest compared to pre-treatment levels. Concentrations of Mg and K were still significantly above pretreatment levels 17-X years following harvest. Calcium concentrations did not change significantly at the IO-30 cm depth, but both Mg and K showed significantly higher concentrations m some post-treatment years. Soils in the adjacent reference watershed showed ?io significant changes in soil cation concentrations over the same l7-year period. Results indicate that sawlog harvest using cable-yarding techniques on these sites does not adversely impact soil cation concentrations. b 1997 Elsevier Science B.V. K~Jww~.<: Forest management: Soil chemtbtry; Nutrient availability