These guidelines - intended for a global audience of decision-makers, civil servants, policy advisors and other stakeholders - promote urban and peri-urban forests as a way of meeting the needs of cities for environmental services. They will also raise community awareness on the positive contributions that urban and peri-urban forests can make to city life and their essential role in global sustainability.

Many people worldwide lack adequate access to clean water to meet basic needs, and many important economic activities, such as energy production and agriculture, also require water. Climate change is likely to aggravate water stress. As temperatures rise, ecosystems and the human, plant, and animal communities that depend on them will need more water to maintain their health and to thrive. Forests and trees are integral to the global water cycle and therefore vital for water security – they regulate water quantity, quality, and timing and provide protective functions against (for example) soil and coastal erosion, flooding, and avalanches. Forested watersheds provide 75 percent of our freshwater, delivering water to over half the world’s population. The purpose of A Guide to Forest–Water Management is to improve the global information base on the protective functions of forests for soil and water. It reviews emerging techniques and methodologies, provides guidance and recommendations on how to manage forests for their water ecosystem services, and offers insights into the business and economic cases for managing forests for water ecosystem services. Intact native forests and well-managed planted forests can be a relatively cheap approach to water management while generating multiple co-benefits. Water security is a significant global challenge, but this paper argues that water-centered forests can provide nature-based solutions to ensuring global water resilience.

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.