Forest Trees Under Air Pollution as a Factor of Climate Change

Air pollution and climate change are inherently linked to each other. After introducing into the presently prevalent air pollutants and their relevance for forest tree and ecosystem performance, the account focuses on nitrogen deposition and tropospheric ozone (O3), the latter being regarded as potentially most detrimental to vegetation, and hence, as negating carbon sink strength and storage. Mechanisms of O3 action in trees and stands are highlighted, stressing interactions with other abiotic and biotic factors, including volatile organic compounds, as a fundamental pre-requisite for understanding O3 effects. O3 is emphasized as a globally effective agent of climate change, regarding relevance for forest productivity, in particular, at hot spots of air pollution in the southern hemisphere, prognosticated for the upcoming decades. Adaptation capacities of forest trees are discussed in view of the rapidity in the progression of environmental change.