Western White Pine (Pinus monticola; family Pinaceae) is a species of pine that occurs in the mountains of the western United States and Canada, specifically the Sierra Nevada, the Cascade Range, the Coast Range, and the northern Rocky Mountains.

Western White Pine is a large tree, regularly growing to 30-50 m and exceptionally up to 70 m tall. It is a member of the white pine group, Pinus subgenus Strobus, and like all members of that group, the leaves ('needles') are in fascicles (bundles) of five, with a deciduous sheath. The needles are finely serrated, and 5-13 cm long. The cones are long and slender, 12-32 cm long and 3-4 cm broad (closed), opening to 5-8 cm broad; the scales are thin and flexible. The seeds are small, 4-7 mm long, and have a long slender wing 15-22 mm long.

It has been seriously affected by the White Pine Blister Rust (Cronartium ribicola), a fungus that was accidentally introduced from Europe in 1909. The United States Forest Service estimates that 90% of the Western White Pines have been killed by the blister rust west of the Cascades. Large stands have been succeeded by other pines or non-pine species. The rust has also killed much of the Whitebark Pine outside of California.

The US Forest Service has a program for locating and breeding rust-resistant Western White Pine and Sugar Pine (see external link below). Seedlings of these trees have been introduced into the wild.

External link

US Forest Service Dorena Tree Improvement Center