The U.S. Department of Agriculture’s Forest Service manages more than 779,000 km2 (193 million acres) of national forests and grasslands (collectively, National Forest System [NFS] lands) that play a significant role in providing clean, fresh water for local ecosystems and economies. This water is sometimes transferred hundreds of kilometers away to also serve big cities through inter-basin transfers (IBTs). The contribution of NFS lands to surface drinking water supplies for public water systems has not been assessed at the national scale while accounting for IBTs. The Forest Service Water Supply Stress Index (WaSSI) model was modified to provide estimates of 2001–2015 mean annual surface water supply and the proportion of mean surface water supply originating on 172 NFS land units and other forested lands at the 12-digit hydrologic unit code scale across the conterminous United States (CONUS) while accounting for water transfer through IBTs. Predictions of the proportion of surface water supply originating on NFS and other forested lands were linked to specific downstream communities and populations, using surface drinking water intake information from the U.S. Environmental Protection Agency Safe Drinking Water Information System database of public water systems. A new database of 594 IBTs was compiled for this study, ranging from 0.01 million m3 yr-1 to 8,900 million m3 yr-1, for a total transferred volume of 116,894 million m3 yr-1. Overall, NFS lands comprised 9.2 percent of the total CONUS land area but contributed 12.8 percent of the surface water supply. In the West, NFS lands comprised 19.2 percent of the total land area but contributed 46.3 percent of the 478.7 billion m3 yr-1 surface water supply; in the East, NFS lands comprised about 2.8 percent of the total land area and 3.8 percent (66.6 billion m3 yr-1) of the surface water supply. In total across the CONUS, NFS and other forested lands comprised 28.7 percent of the total land area but contributed 46.0 percent of the surface water supply. Approximately 45.8 million people derived >10 percent of their surface drinking water supply from NFS lands, and 22.6 million people received >50 percent of their surface drinking water supply from NFS lands. Approximately 125.5 million people, about 39 percent of the total population in the CONUS in 2017, derived >10 percent of their surface drinking water supply from NFS and other forested lands, with 83.1 million people receiving >50 percent of their surface drinking water supply from NFS and other forested lands. In addition to those populations receiving surface drinking water supply from their local public surface drinking water intakes, 12.6 million people were served by public water systems that purchased surface drinking water supply from other public water systems deriving >10 percent of their surface drinking water supply from NFS lands. This study provides a systematic accounting of NFS and other forested lands for surface drinking water supply. Our results can aid water resource and forest managers in developing integrated watershed management plans at a time when climate change, population growth, and land development threaten water supplies.

Forests and water are inextricably linked, and people are dependent on forested lands to provide clean, reliable water supplies for drinking and to support local economies. These water supplies are at risk of degradation from a growing population, continued conversion of forests to other land uses, and climate change. Given the variety of threats to surface water, it is important for forest managers to know how much of the drinking water supply originates in forests they manage and what populations and communities are served by that water. The objective of this analysis was to address this need by 1) estimating how much fresh surface water supply in the South originates from NFS lands and State and private forest lands, and 2) estimating how many people and which communities in the South depend on this fresh surface water supply. Of the 6,188 intakes, 3,143 received more than 20 percent of their water from State and private forest lands and served 29.0 million people. These results highlight the importance of southern forests in providing clean and dependable water supplies to downstream communities.

This guide showcases the increasing interest in ecosystem services, discusses the motivations for valuations of FES (forest ecosystem services) at the State level, and places this work in the context of economic accounting. Readers may be interested in this report to expand their understanding of approaches used and value forest ecosystem services. However, the intended target audience for this report is State forestry officials charged with requesting, selecting, guiding, and evaluating the results of FES assessments in their states. Foresters, construction officials utilizing forest based products, educators, instructors and students in the fields of environmental science and forestry, environmentalists, and investors in the forest products category may also be interested in this work. Check out our Environment & Nature resources collection here:https://bookstore.gpo.gov/catalog/environment-nature Trees & Forests collection here:https://bookstore.gpo.gov/catalog/environment-nature Water Management collection here: https://bookstore.gpo.gov/catalog/water-management

Future Forests: Adaptation to Climate Change provides background on forests as natural and social systems, the current distribution and dynamics based on major biomes that set the stage for their role of forests in global systems, the nature of climate change organized by biomes, and detailed descriptions of mitigation and adaptation strategies. This book forms presents a foundational summary of the feedback between the effect of climate change on forests and the converse effects of forests on climate, leading to conclusions on how forest management needs to be dictated by climate change.The book will be ideal for readers in the fields of climate change science, forest science and conservation biology, helping them develop a thorough understanding on the broad perspective of climate change on forests, the response of forests to these changes, and other climate-forest interaction potentials. Organizes information on climate change and the effect of/on forests at a general level before presenting biome-related specifics Discusses the differences among major biomes (tropical, boreal, temperate) and the systems in which forest management (and hence potential mitigation and adaptation) occurs Goes beyond simply describing problems, elaborating on potential solutions that can be implemented for climate change mitigation