Evidence suggests that efforts to eradicate the Asian long-horned beetle appear likely to succeed, while the emerald ash borer and P. ramorum are likely to continue to infest and damage forest ecosystems indefinitely despite efforts to control them. The Asian long-horned beetle is a wood-boring insect from Asia that has caused separate infestations in parts of New York, New Jersey, and Illinois. Over 8,000 trees infested with the beetle have been removed, and over 600,000 trees have been chemically treated to protect against the beetle. As a result of these and other actions, federal and state agencies have been able to reduce the size of the infested areas. The emerald ash borer is also a wood-boring insect from Asia that has infested large areas in Michigan; Ohio; Indiana; and Ontario, Canada, killing an estimated 15 million trees. The pathogen P. ramorum is the causal agent of the disease known as Sudden Oak Death. It is of unknown origin and has infested large areas in central and northern coastal California and a small area in southern Oregon. This book examines these key environmental issues. This book is a fully-indexed excerpted version of a GAO report.