The Effects of Acidic Deposition and Ozone on Forest Tree Species in the Eastern United States: Results from the Forest Response Program

Abstract

By the early 1980s in North America, several researchers reported problems in northeastern spruce-fir forests. Johnson and Siccama (1983) reported that since the early 1960s red spruce forests at high elevations in New York, Vermont, and New Hampshire have shown dieback and large reductions in basal area and density that are characteristic of a stress-related disease. Because of the locations of these forests, it was suggested that climatic stresses, such as drought, and pollutants in the form of acid deposition and airborne trace metals may contribute to the decline. Hornbeck and Smith (1985) used tree cores from a broad-scale survey of New England low-elevation, dominant, and codominant red spruce and found a large reduction in tree basal area increment occurring since the early 1960s. Reports of red spruce decline are not restricted to the northeast. Bruck (1984) and Adams et al. (1985) reported red spruce declines in the southern Appalachian Mountains.