Scientific name: Pinus strobus Linnaeus 1753

Synonyms: Leucopitys strobus (L.) Nieuwl., Pinus nivea Booth ex Carrière, Pinus tenuifolia Salisb., Pinus umbraculifera K.Koch, Strobus strobus (L.) Small, Strobus weymouthiana Opiz

Common names: Eastern white pine, Northern white pine, White pine, Weymouth pine, Pin blanc (French)

Description

Tree to 35(-60) m tall, with trunk to 1.5(-1.8) m in diameter. Bark light grayish brown, smooth at first, becoming broken into vertical, rectangular blocks by shallow to deep cracks. Crown conical at first, becoming flat-topped, cylindrical, and irregularly open with age , with wide-spreading, horizontal branches of variable length reasonably densely clothed with foliage near their ends. Twigs pale reddish brown, hairless or a little hairy at first. Buds 4-8(-15) mm long, slightly resinous or not. Needles in bundles of five, each needle (5-)6-10(-15) cm long, straight or arching, thin and flexible, lasting 2-3 years, dark green to bluish green. Individual needles with lines of stomates only on the inner faces, an undivided midvein, (one or) two resin canals touching the epidermis of the outer face, and sometimes with a third resin canal touching the epidermis of one or the other inner face near the angle where they come together. Sheath 10-15 mm long, soon shed. Pollen cones 5-15 mm long, straw-colored. Seed cones (6-)8-20(-25) cm long, taperingly cylindrical and pointed at both ends, often curved, with 40-100 seed scales, yellowish green to bluish green or even purple-tinged before maturity, ripening light brown, opening widely to release the seeds, with a slender stalk (1-)2-4.5 cm long. Seed scales egg-shaped, thin and a little flexible, the exposed tips straight, the narrow, diamond-shaped umbo straight or slightly hooked inward. Seed body (5-)6-8(-9) mm long, egg-shaped, the firmly attached wing 18-25(-30) mm long.

Eastern North America in southeastern Canada, northeastern and east-central United States, southern Mexico, and southwestern Guatemala. Forming pure stands, or more commonly mixed with red pine (Pinus resinosa) and other conifers and numerous hardwoods on a variety of soil types; 0-1,500(-2,200) m.

Conservation Status

Red List Category & Criteria: Least Concern

The vast extent of occurrence (EOO) in North America and the fact that the variety Pinus strobus var. strobus in many places is now again spreading and increasing, places it firmly as Least Concern. This assessment of the typical variety determines that of the entire species. In North America this species is abundant over a huge range. Pinus strobus is widely (and disjunctly) distributed in regions as widely different in climate and topography as Newfoundland and Chiapas, Mexico. The variety strobus is confined to the NE part of the species range, where winters are cold and snowy; var. chiapensis occurs in the wet mountains with frequent fog in the southern part. These populations were once connected, presumably as late as the last Ice Age, when Pinus strobus and other trees were all pushed southward before the advance of the Laurentide Ice Sheet. In the northern part, Pinus strobus mainly grows in the lowland hills around the St. Lawrence River and the Great Lakes, in the Appalachian Mountains to 1,200 m a.s.l. In its southern extension it is confined to much higher altitudes between 800 m and 2,200 m a.s.l. Annual precipitation varies greatly from area to area, with lows at around 500 mm and highs in Mexico to 3,000 mm. The southern var. chiapensis experiences no frost, while long and cold winters are the norm in most of the range of var. strobus. Both varieties are major or minor components of mixed forests, with other conifers and/or with broad-leaved trees. There is a similarity of several broad-leaved (angiosperm) tree species in the forests of the southern Appalachians and the mountains of Veracruz and Chiapas, Mexico, but in the colder north Pinus strobus grows with species not common to both the northern and southern ranges. The vast resources of timber available to European colonists from this large pine had been depleted towards the end of the nineteenth century. However, as regrowth occurred, this has not threatened the continued existence and occurrence of the species significantly. Hence, while old growth Eastern White Pine is now very rare, under the Red List Criteria Pinus strobus is not under threat. The situation with var. chiapensis in Mexico and Guatemala is more serious, with deforestation the main threat, followed by targeted logging of this valuable timber. Eastern White Pine was once the most important timber tree in eastern North America and in colonial times the British government forbade European colonists to cut the larger trees (marked with the 'broad arrow') as it wished to reserve these for the British Navy as ship masts. Its fine grained, smooth textured wood low in resin makes excellent construction timbers, while doors and windows, furniture, and matches are other uses. In the USA and Canada it is widely planted both for timber and for urban planting as shelter belts, as well as restoration of areas disturbed by strip mining of coal. Americans and Canadians use this pine for Christmas trees as its foliage can be clipped into shape. As an ornamental tree it is not very common in Europe, probably due to susceptability to White Pine Blister Rust (Cronartium ribicola, Basidiomycota) and poor shape in cultivation. Attempts at forestry plantation in Britain also failed due to this disease, as well as to aphid insect predation (Pineus strobi). In the colder, drier winters of North America it thrives better; several cultivars are well known and used in gardens, especially some of the dwarfed forms. This species is known from several protected areas within its extensive range.

References

Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.
Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.
IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland