whitebark pine

The whitebark pine (Pinus albicaulis) is a pine tree native to the western United States. It is characterized by its thin, pale brown or creamy white bark and soft, brittle wood. The term "whitebark" can also refer to other trees with pale bark, such as the white poplar.12

A significant threat to whitebark pines is blister rust, a disease caused by rust fungi. White pine blister rust, in particular, is a virulent disease that was introduced to North America around 1900. It affects five-needled pine species and has severely depleted whitebark pine stands. The disease damages the sapwood and inner bark, leading to blisters that release spores and cause resin to ooze. This weakens the trees, retards their growth, and can be lethal, especially for younger trees.3