National forests of the dry, interior portion of the western United States that are managed by the Department of Agriculture's Forest Service have undergone significant changes over the last century and a half, becoming much denser, with fewer large trees and many more small, tightly spaced trees and underbrush. These changes have raised concerns about the current health of these forests and their continued ability to provide for sustained levels of uses, including timber and wildlife habitat, by future generations of Americans, as required by law. In response to a request from the Subcommittee on Forests and Forest Health, House Committee on Resources, GAO examined issues related to the health of these forests. In this report, GAO discusses (1) the extent and seriousness of forest-health-related problems on national forests of the interior West, (2) the status of efforts by the Forest Service to address the most serious of these problems, and (3) barriers to successfully addressing these problems and options for overcoming them.