摘要:Idaho has more than 21.4 million ac (8.6 million ha) of some of the most diverse forests in the Rocky Mountains. The largest part (76 percent) of Idaho’s forests is managed by the U.S. Department of Agriculture (USDA), Forest Service, but, progressing north, forests owned by families, the State of Idaho, and forest product companies are increasingly more prominent. Most ownerships seek to reduce stand density and shift species composition to reduce fire risk and insect and disease issues. Idaho has a strong tree improvement program, originating from efforts to develop blister rust-resistant western white pine seedlings. Idaho has two USDA Forest Service seedling nurseries, a nursery managed by the University of Idaho (UI), and a few private seedling nurseries. Highly varied sites present likewise varied challenges to Idaho tree planting. Common threats to seedling survival include seedling moisture stress; rodents (particularly pocket gophers); deer, elk, and moose; and white pine blister rust.