Limber Pine

(Pinus flexilis)

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Limber Pine (Pinus flexilis)

Identifying Characters: Needles in bundles of 5 and sheaths deciduous after the first year; cones 3-10 inches long; cones on a very short stalk and elongate-ovate.

Similar Species: Limber Pine is most closely related to Southwestern White Pine. The cones of Southwestern White Pine are generally larger than those of Limber Pine (6-10 inches versus 3-6 inches). The needles of Southwestern White Pine are bright green, not dark green and white lines are found only on the ventral surface, not all around as in Limber Pine. The ranges of the two species do not overlap. Southwestern White Pine is found in middle to southern Arizona and New Mexico, but Limber Pine ranges from northern Arizona and northern New Mexico northweard. Limber Pine resembles Whitebark Pine, but the cones of Limber Pine are longer (3-6 inches long versus 1.5 to 3 inches long in Whitebark Pine).

Measurements: Height averaging 20 to 30 feet with rare individuals reaching 60 feet; diameter of trunk 2 to 4 feet in mature individuals.

Cones: Cones 3 to 6 inches long, egg-shaped and elongate, with a short stalk; scales elongate-rounded and ending in a blunt point; scales of cone open at maturity.

Needles: Needles are evergreen, from 1-1/2 to 3 inches long, dark to medium green with white lines on all surfaces; needles in bundles of 5 and sheath shed after the first year.

Bark: Bark 1 to 2 inches thick, dark brown or gray black, divided by fissures into broad ridges broken into nearly square plates covered by small scales.

Native Range: Limber Pine grows from Alberta and southeastern British Columbia to New Mexico, Arizona, and eastern California. Notable outliers of this general distribution are found in the western portions of North Dakota, South Dakota, and Nebraska, and in eastern Oregon and southwestern California. (Silvics of North America. 1990. Agriculture Handbook 654.)

Habitat: In the northern half of its distribution, Limber Pine is generally found near lower tree line and on dry sites in the montane forests. Between the 45th and 40th parallels, it grows in both lower and upper elevation forests and anywhere in between on dry, windswept sites. Its position gradually shifts upward in more southerly latitudes, so that in southern portions of its distribution, Limber Pine is more common from upper montane to alpine tree line, with only minor occurrences in the lower forested zones. Because of this adaptability, Limber Pine ranges in elevation from about 870 m (2,850 ft) in North Dakota to about 3810 m (12,500 ft) in Colorado.