Most people do not realize that more than half the water in the United States comes from watersheds managed on forests. Used in homes, on ranches, in industry and for energy production, water resources in forests provide important services to people, as well as habitat for a wide variety of aquatic life. Our rapidly changing climate, however, is challenging our watersheds with both wet and dry extremes - more severe droughts, more frequent and larger floods, more soil moisture stress and lower stream flows during the dry season, less of a snowpack reservoir, and other effects. In a unique pilot project, 11 national forests around the country are assessing the vulnerability of their water resources and watersheds to such changes.