Bringing nature into the city -- The principles of an effective urban forestry program -- Case studies -- Conclusions and recommendations. "Urban forests provide enormous environmental, social, and economic benefits. In addition to aesthetics, urban forests conserve natural ecosystems and sustain clean air and water. They reduce stormwater runoff, cool the urban heat island, reduce air pollution, and provide wildlife habitat. Yet the tree canopy in many U.S. metropolitan areas has declined significantly over the last few decades due to increased urbanization. The solution is far more complex than planting more trees, however. Urban forestry professionals and advocates must maximize green infrastructure (the natural environment) while reducing the costs of gray infrastructure (the built environment). While both are important, communities that foster green infrastructure are more livable, produce fewer pollutants, and are most cost-effective to operate. This report, prepared by the American Planning Association (APA) in collaboration with the International Society of Arboriculture (ISA) and American Forests (AF), and supported by the USDA Forest Service, addresses the need for planners to adopt a green infrastructure approach and presents guidelines for incorporating trees into the planning process."--Pub. desc.