Artificial watershed acidification on the Fernow Experimental Forest, USA

Abstract

A whole-watershed manipulation project was begun on the Fernow Experimental Forest in West Virginia, USA, in 1987, with the objective of increasing understanding of the effects of acidic deposition on forest ecosystems. Two treatment watersheds (WS9 and WS3) and one control watershed (WS4) were included. Treatments were twice-ambient N and S deposition, applied via NH 4SO 4 fertilizer, with three applications per year. Three years of pretreatment data were collected and used for calibration. Stream water chemistry data collected during 3 years of treatment were evaluated. Stream water pH and electrical conductivity were not significantly affected by the elevated N and S inputs on either treatment watershed. On WS9, there were no statistically significant treatment effects on stream water export of Ca, SO 4, or NO 3. On WS3, however, stream export of both NO 3 and Ca have increased as a result of acidification treatments. The implications of these results are discussed. Research is continuing so that the processes involved may be elucidated. In addition, effects on vegetation, aquatic invertebrates and amphibians also are being evaluated.