Approaches for estimating critical loads of N and S deposition for forest ecosystems on U.S. federal lands
Gen. Tech. Rep. NRS-71. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 25 p.
Projected emissions of sulfur and nitrogen are expected to have continuing negative impacts on forests, in spite of reductions in sulfur emissions as a result of SO2 control programs. Sulfur and nitrogen emissions present serious long-term threats to forest health and productivity in the United States. This report is intended to explain the differences in approaches for calculating critical loads for forest ecosystems in Europe, Canada, and the United States; it is directed to air quality regulators and Federal Land Managers (FLMs) in the United States, and addresses concerns particular to U.S. Federal lands. The paper describes the basic mass balance approach for calculating critical loads, presents the various critical thresholds, and explains the assumptions inherent in the calculation and data selection procedure. The input necessary from FLMs in the process of estimating the critical load is described.
Keywordsbase cation depletion; nitrogen saturation; simple mass balance model
Pardo, Linda H. 2010. Approaches for estimating critical loads of N and S deposition for forest ecosystems on U.S. federal lands. Gen. Tech. Rep. NRS-71. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 25 p. https://doi.org/10.2737/NRS-GTR-71.