van Noordwijk, Meine; Creed, Irena F; Jones, Julia A; Wei, Xiaohua (Adam). 2018. Chapter 2: Climate-Forest-Water-People Relations: Seven System Delineations. In: Forest and Water on a Changing Planet: Vulnerability, Adaptation and Governance Opportunities. A Global Assessment Report. IUFRO World Series; Volume 38. Vienna: International Union of Forest Research Organizations (IUFRO): 27-59.
Water security is key to achieving the United Nations’ Sustainable Development Goals (SDGs). In what has been called a new era of
the Anthropocene, the changes we are inflicting on our planet are influencing the current and future availability of ecosystem services of importance to our survival. And provision of clean water is the most basic ecosystem service
necessary for life on earth. Yet, increasingly we are facing water shortages, and an estimated four billion people do not have sufficient access to safe and reliable water.
Whereas the link between forests and climate is regularly considered in decision-making, that between water and forests remains under-represented. Even more importantly, water, forests and climate are intrinsically interlinked,
but this relationship is still poorly understood when it comes to decision-making.
Forests influence water resources in multiple ways, and at multiple levels. Generalisations fail to capture these intricate interlinkages. Soils, rooting depth, leaf area and stems are key features of trees and forests that determine the way an individual tree uses water and consequently, its impact on water resources. Species diversity and age structure of a forest in turn
influence the above four key factors. At landscape scales, the diverse mosaic of land use that typifies human-dominated landscapes, also determines the way forests and trees are able to influence water availability and quality. Recent recognition of the role of forests in downwind generation of precipitation further expands the geographical scope of the intricate
relationship between water and forests.
Today, the fact that the world has mobilised around 17 SDGs, all of which have a connection to water, provides a crucial argument for paying more attention to the forest-water link. Policymakers are facing new challenges in implementing the multiple water-related objectives across the portfolio of SDGs. While the international community agreed the SDG framework
based on moral principles, science is essential for developing the policies and practices required in achieving the related targets.
Led by IUFRO, the Collaborative Partnership on Forests’ Global Forest Expert Panels (GFEP) initiative undertook a comprehensive scientific
assessment of the state of knowledge on the forest-water relationship. This policy brief summarises the key messages of the report completed by the GFEP on Forests and Water.