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Individual Highlight

Declining Acidic Deposition Begins Reversal of Forest-Soil Acidification

Photo of Sampling forest soil at Equinox Preservation Trust, Vermont. Rick LaDue, Equinox Preservation Trust.Sampling forest soil at Equinox Preservation Trust, Vermont. Rick LaDue, Equinox Preservation Trust.Snapshot : How are forest soils recovering from acid rain? An international collaboration found improvements in soil quality that indicate recovery is on the way and elucidate important recovery mechanisms.

Principal Investigators(s) :
Bailey, ScottSmith, Kevin T.
Research Location : Northeastern U.S., Ontario and Quebec, Canada
Research Station : Northern Research Station (NRS)
Year : 2016
Highlight ID : 1036


Acid deposition, resulting from sulfur and nitrogen air pollution, acidified surface waters and soils in sensitive areas throughout the northern hemisphere. Resulting changes in soil chemistry contributed to the decline of many forest and aquatic species. The Clean Air Act of 1990 reduced acid deposition and improved surface water quality. New Forest Service research includes the first reports of initial improvement in soil quality due to decreased deposition of acid rain. Recovery of soil relative to surface water is delayed due to the slow pace of mineral decomposition. Additional research points to wood decay as a relatively more rapid contributing pathway to restore the health and fertility of forest soil. The Northeastern Soil Monitoring Cooperative was formed across the northeastern United States and adjacent Canada, particularly hard hit by acid rain, to determine the scope of soil recovery and to validate the success of air pollution regulation and natural cycling process to restore forest soil health.

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