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Forests are facing significant pressures from climate change and air pollution. Air pollution is the main driver of the ongoing climate change. Current knowledge suggests that climate change may become more harmful to pollution-affected forests, although the magnitude of these feedbacks is still to be determined. At present, the air pollutants of most concern to forests are tropospheric ozone a nd nitrogen deposition. Both ozone and nitrogen affect biodiversity and increase forest susceptibility to drought, pest attacks, windstorms and fire. The impacts on forest ecosystems, however, have traditionally treated air pollution and climate change separately, although they are, in fact, cause and effect. The cause and effect relationship between pollutant inputs and ecological factors or ecosystem attributes requires substantial multidisciplinary research effort. The integrative effects of air pollution and climatic changes, in particular those caused by elevated ozone, altered nutrients, temperature, water availability, and elevated CO2, will be key issues for future research. An important improvement in our understanding will be obtained by the combination of long-term multidisciplinary experiments with ecosystem-level monitoring, and integration of effects utilizing ecosystem modeling within a multiple-constraint framework. This paper reviews the current knowledge on the integrated climate change and air pollution impacts on global forests, and suggests mitigation strategies, adaptive forest management options, and how to close knowledge gaps for appropriate decisions in environmental policy