Whitebark Pine

(Pinus albicaulis)

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Whitebark Pine (Pinus albicaulis)

Identifying Characters: Whitebark Pine may be identified by the bundles of five needles, the deciduous bundle sheaths, the globular cones, and the distinctive bark in older trees.

Similar Species: Whitebark Pine might be confused with Limber Pine within its range. However the cones are smaller and the scales are smaller and less elongate than in the that species. The bark of Whitebark Pine is very distinctive.

Measurements: Mature trees 40 to 50 feet in height, although some individuals may reach 80 feet; diameter 1 to 2 feet.

Cones: Cones 1.5 to 3 inches long, globular; cone scales thickened often with an apical stout, pointed spine; cones remain closed at maturity; cones sessile and dark purple to brown, shed at maturity.

Needles: Needles are 1.5 to 2.5 inches long, thick, rigid, and slightly incurved; needles in bundles of five and sheath shed after the first year; needles clustered near the ends of the branches; color dull green with faint white lines all over.

Bark: Bark white-gray or creamy gray, smooth and thin in young trees, breaking into gray-white scales in older trees.

Native Range: Whitebark Pine grows in the highest elevation forest and at timberline. Its distribution is essentially split into two broad sections, one following the British Columbia Coast Ranges, the Cascade Range, and the Sierra Nevada, and the other covering the Rocky Mountains from Wyoming to Alberta.

Whitebark Pine is abundant and vigorous on the dry, inland slope of the Coast and Cascade Ranges. It is absent from some of the wettest areas, such as the mountains of Vancouver Island. In the Olympic Mountains, it is confined to peaks in the northeastern rain shadow zone. Whitebark Pine also occurs atop the highest peaks of the Klamath Mountains of northwestern California.

The Rocky Mountain distribution extends along the high ranges in eastern British Columbia and western Alberta, and southward at high elevations to the Wind River and Salt River Ranges in west-central Wyoming.

A small outlying population of Whitebark Pine is found atop the Sweetgrass Hills in north-central Montana 145 km (90 mi) east of the nearest stands in the Rocky Mountains across the Great Plains grassland.

The coastal and Rocky Mountain distributions lie only 100 km (62 mi) apart at their closest proximity. Even this narrow gap is not absolute; small groves are found on a few isolated peaks in between in northeastern Washington. In addition to the main distribution, whitebark pine grows in the Blue and Wallowa Mountains of northeastern Oregon and in several isolated ranges rising out of the sagebrush steppe in northeastern California, south-central Oregon, and northern Nevada. (Silvics of North America. 1990. Agriculture Handbook 654.)

Habitat: Whitebark Pine is a timberline or subalpine species occurring on dry, rocky soils on open slopes. The species sometimes occurs in nearly pure stands.