Forests and water

The availability and quality of clean water in many regions of the world is more and more threatened by overuse, misuse and pollution. In this context, the relationship between forests and water must be accorded high priority. Forested catchments supply a high proportion of the water for domestic, agricultural, industrial and ecological needs in both upstream and downstream areas. A key challenge faced by land, forest and water managers is to maximize the benefits that forests provide without detriment to water resources and ecosystem function. There is an urgent need for a better understanding of the interface of forests and trees with water and for embedding this knowledge in policies. This study, initiated in the context of the Global Forest Resources Assessment 2005, highlights the need for holistic management of complex watershed ecosystems taking into account interactions among water, forest and other land uses as well as socio-economic factors. It explains the role of forests in the hydrological cycle, with a particular focus on critical, “red flag” forest situations such as mountainous or steep terrain, river and coastal areas and swamp ecosystems, as well as the special case of mountainous small islands. It addresses the protection of municipal water supplies and emerging systems of payment for watershed services. This state-of-knowledge publication will be of interest to a broad range of technical experts, scientists and decision-makers.