Project Overview

In 1987, in response to concerns about the impacts of atmospheric deposition, commonly referred to as “acid rain,” on forest ecosystems, the US Environmental Protection Agency (EPA) provided funds for the establishment of Bear Brook Watershed Research Site, Maine (BBWM), as a Watershed Manipulation Project (WMP) under the National Acid Precipitation Assessment Program (NAPAP). BBWM was established to identify atmospheric deposition impacts on surface waters and to quantify the major processes controlling surface water acidification under increased sulfur (S) and nitrogen (N) atmospheric deposition.


The initial research at BBWM included assessing impacts of elevated loading of acidic or acidifying substances on forest soils. In more recent years research has begun to examine the impacts of atmospheric deposition on the forest vegetation at BBWM. In 1996, long- term monitoring of the forest vegetation, employing the methodologies of the national Forest Health Monitoring (FHM) program, was undertaken.

Dataset Availability

By request: 15 datasets

See the full list of available data


Status - Completed

Start date: 1997-07-01

End date: 1999-08-31

Study Area

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