ABSTRACT
This chapter focuses on atmospheric pollutants and contaminants which are deposited to forest canopies and affect tree physiology or plant community dynamics, influence biogeochemistry at the stand and watershed level, or are cycled through or altered by forests and subsequently influence human health. It describes the attributes of air pollution that are important to investigating ecological effects in forests. The chapter explains some of the methodologies used to address air pollution effects in forests. It aims to provide a case study demonstrating the presence of multiple air pollutants in many North American forests. Multiple pollutant recognition has prompted the development and application of new methodologies which take into account the uniqueness of unmanaged forest ecosystems, their responsiveness to air pollution, and the role of multiple stress interactions. Ozone is well documented to affect the physiology of at-risk forest tree species on a regional, hemispherical, and global scale.
