This report on the major insect and disease conditions of the Nation's forests represents the 65th annual report prepared by the U.S. Department of Agriculture, Forest Service. The report focuses on 19 major insects and diseases that annually cause defoliation and mortality in U.S. forests.Insects and diseases play critical roles in maintaining healthy, resilient ecosystems, but they are also among the most serious environmental and economic threats to the millions of acres of forests and urban treed areas in America. Natural and anthropogenic stressors will continue to influence the establishment, spread, and impacts of insects and diseases on forests. Tree species may be positively or negatively impacted by these changes, altering the array of products and services derived from forested lands, including timber, recreation, clean water, energy, wildlife habitat, and jobs. To understand how conditions are changing and to protect species, forests are surveyed for insect and disease extent and intensity so that Federal and State agencies and other stakeholders can prioritize future actions and ensure forests remain resilient and sustainable into the future. The overall mortality caused by insects and diseases varies by year and by pest.

After the first Euro-American settlers arrived in Seattle in the 1850s, the surrounding old-growth forests were rapidly harvested for lumber, causing environmental degradation and displacing native peoples. Conflicts about the future of Pacific Northwest forests have continued since then. Only recently have academics, government agencies, industry, small private landowners, tribes, and environmental organizations come together to develop plans to protect the remaining old-growth forests, wildlife, streams, and fish, as well as providing environmentally friendly forest products. Practicing sustainable forestry, maintaining healthy forests that are less susceptible to fire, insects and diseases; and fostering public enjoyment are now the main goals of forest management. However, conflicts still exist—and with climate change a looming threat, it is important to realize that forests give us much more than lumber. Robert L. Edmonds, professor emeritus at the School of Environmental and Forest Sciences, University of Washington (UW), wrote this book to bring attention to the sustainability of natural resources. He describes how Washington State’s forests and the practice of forestry have changed through time and how these changes relate to the long history of research and teaching at the UW. Its scope extends beyond Washington—many of the principles of sustainable forestry developed by faculty have been adopted worldwide.