Impact of harvesting and atmospheric pollution on nutrient depletion of eastern US hardwood forests

The eastern hardwood forests of the US may be threatened by the changing atmospheric chemistry and by changes in harvesting levels. Many studies have documented accelerated base cation losses with intensive forest harvesting. Acidic deposition can also alter nutrient cycling in these forests. The combination of increased harvesting, shorter rotations, and more intensive harvesting, along with the potential for N and S saturation due to changing atmospheric chemistry in the eastern US, raises concerns about the long-term productivity of these commercially important eastern hardwood forests. We review the literature describing the effects of intensive harvesting and acidic atmospheric deposition on budgets of base nutrients which presents evidence that the ambient levels of N and S deposition are leading to N and S saturation and elevated base leaching from the soil in some eastern forests, and we discuss potential concerns for long-term productivity. We also discuss criteria and indicators for monitoring sustainability of the soils of these forests. (C) 2000 Elsevier Science B.V. All rights reserved.