Acidic deposition and sustainable forest management in the central Appalachians, USA

Long-term productivity of mixed-species forests in the central Appalachian region of the United States may be threatened by changes in base cation availability of the soil. These changes may be due to increased intensity of harvest removals and a shift toward shorter rotations that result in increased removal of calcium and magnesium in aboveground biomass, and through altered nutrient cycling. Atmospheric deposition, particularly of nitrogen, also affects nutrient cycling by increasing leaching of base cations from the soil in soil solution, and by altering the rate of nutrient cycling. In this paper, I present evidence for nitrogen saturation of forested ecosystems in the central Appalachians, discuss the symptoms and implications for productivity as well as the effects of changes in timber harvesting rates and intensity on nutrient cycling, and evaluate the potential for interaction between these two stressors. Indicators of changes in productivity of extensively managed forests due to base cation depletion are also discussed. (C) 1999 Elsevier Science B.V. All rights reserved.