Response of Eastern Hardwood Species to Ozone, Sulfur Dioxide and Acid Precipitation

Abstract

Recent reports and observations of dieback, declines, and reduced growth in forests in the Eastern States have lead to an attempt to determine if atmospheric deposition is a major causal factor in these disorders. In the red spruce and southern pine forest where these abnormalities are either visible or have been documented by research data, studies are underway to determine the mechanisms involved and the role of atmospheric deposition. In the eastern hardwood forest there are reasons to suspect similar phenomenon, but because of the more complex nature and the wider species diversity in these forests the declines are more difficult to document. Another factor that increases the difficulty in determining whether atmospheric deposition is affecting hardwood forests is that tree responses to most stress factors, including atmospheric deposition, are very similar. The objective of this study was to determine the relative sensitivity and symptom development of 10 hardwood tree species to ambient levels of common gaseous pollutants.