A tree 20 to 30 ft in the wild, but taller in cultivation; bark of mature trees thick, roughly fissured; young shoots often curiously twisted, glabrous; terminal buds narrowly cylindrical, 3⁄4 to 1 in. long, resinous. Leaves in pairs, 11⁄2 to 21⁄4 in. long, 1⁄12 in. or less wide, dark green, persisting three, four, or more years; leaf-sheath 3⁄16 in. long, persistent. Cones obliquely conical, up to 2 in. long, 3⁄4 in. wide at the base before expanding; scales terminated by a slender spine which wears away in time.
Native of the coast region of western N. America, from Alaska to S. California; discovered by Douglas in 1825; introduced shortly before 1855. It belongs to the group of two-leaved pines with persistent leaf-sheaths, and cylindrical, resinous winter-buds. In the absence of cones it might be confused with the mountain pine of Europe, P. uncinata, but in that species the leaves persist for five to ten years and the leaf-sheath is longer – up to 5⁄8 in. long.
In recent years P. contorta has become an important forestry tree in Britain, especially as a pioneer tree on poor peaty soils. Among the largest specimens in collections are: Grayswood Hill, Haslemere, Surrey, pl. 1886, 66 × 83⁄4 ft (1971); Warnham Court, Sussex, 73 × 91⁄4 ft (1971); Westonbirt, Glos., in Broad Drive, 61 × 9 ft (1970); Bodnant, Denb., pl. 1876, 105 × 93⁄4 ft (1974); Ashford Castle, Co. Mayo, Eire, 88 × 121⁄4 ft (1966).
P. contorta, in the wide sense, is a very variable species and there is no unanimity as to how it should be subdivided. The two varieties treated below are not clearly demarcated and are themselves variable. The complex is discussed by W. B. Critchfield in Geographic Variation in Pinus contorta (Maria Moors Cabot Foundation Publ. Vol. 3, 1-118 (1957)).
var. latifolia S. Wats. P. murrayana and P. contorta var. murrayana of most authors, in part; P. contorta subsp. latifolia (S. Wats.) Critchfield Lodgepole Pine. – From typical P. contorta this variety can be distinguished by the thin bark of its trunk (rarely more than 1⁄4 in. thick) of a pale grey or brown, covered with thin scales, but comparatively smooth; also by its longer, yellowish green leaves; the leaves also tend to be rather wider, but the difference is not marked or consistent enough to be of much value in identification. The tree itself attains to a considerably greater height than typical P. contorta and, compared with var. murrayana, the trunk is slender, rarely more than 1 ft in diameter in trees a century old. It is a closed-cone pine, shedding only a small proportion of its seed each year. The bulk of the cones remain closed on the tree for a considerable period, but release their seed in vast quantities after a forest fire. In this way it quickly colonises the devastated area and dense, even-aged stands grow up.
Whereas typical P. contorta inhabits the coastal region, the var. latifolia is a native of the Rocky Mountains, ranging from W. Alaska to Colorado, and ascending to 11,000 ft at the southern end of its range (to 6,000 ft in British Columbia). It was introduced shortly before 1855.
var. murrayana (Balf.) Engelm. P. murrayana Balf.; P. contorta subsp. murrayana (Balf.) Critchfield; P. tamrac A. Murr. – This variety is tall-growing, like var. latifolia, but is much stouter, with a trunk 3 ft or more in diameter. It also differs in its pinkish bark, in bearing cones that usually shed their seed when ripe and soon fall from the tree, and in its rather broader leaves, up to 1⁄10 in. wide. It is confined to the Cascade range and inner California and was discovered and introduced by Jeffrey, who collected cones for the Oregon Association in autumn 1852. No mature specimen has been traced but there are young trees in the trial plots of the Forestry Commission, which grow very slowly.