Acidic Deposition: State of Science and Technology. Report 18. Response of Vegetation to Atmospheric Deposition and Air Pollution

摘要

Air pollutants have been recognized as stress factors for vegetation for well over a century. Historically, problems were associated with localized effects around point sources of pollutants such as sulfur dioxide and hydrogen fluoride. Regional-scale vegetation damage by photochemical oxidants has been recognized for approximately 40 years, and the potential for regional-scale impacts of acidic precipitation on terrestrial ecosystems has been recognized for about 20 years. The document summarizes the mechanisms by which crop and forest vegetation respond to stress in the form of gaseous air pollutants and acidic precipitation. The adequacy of existing data, and the uncertainties associated with use of the data for regional-scale assessment are evaluated. Methods for developing such an assessment given the current state of science are discussed. Major challenges remain in the areas of interpretation of research results from controlled exposure experiments in terms of their relevance to either agricultural crop production or forest stand growth. Remaining knowledge gaps and research needs are summarized.