| Western white pine Pinus monticola | |
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| Western white pine (center) | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Pinales |
| Family: | Pinaceae |
| Genus: | Pinus |
| Subgenus: | P. subg.Strobus |
| Section: | P.sect. Quinquefoliae |
| Subsection: | P.subsect. Strobus |
| Species: | P. monticola |
| Binomial name | |
| Pinus monticola | |
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| Synonyms[3] | |
List
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Western white pine (Pinus monticola), also calledsilver pine[4] andCalifornia mountain pine,[4] is a species ofpine in the familyPinaceae. It occurs in mountain ranges of northwesternNorth America and is thestate tree ofIdaho.
Western white pine is a large tree, regularly growing to 30–50 metres (98–164 ft) tall. It is a member of thewhite pine group,Pinus subgenusStrobus, and like all members of that group, the leaves ('needles') are infascicles (bundles) of five,[5] with a deciduous sheath. The needles are finely serrated,[5] and 5–13 cm (2–5 in) long. The cones, appearing even on young trees, are long and slender,[5] 12–32 cm (4+3⁄4–12+1⁄2 in) long and3–4 cm (1+1⁄4–1+1⁄2 in) broad (closed), opening to5–8 cm (2–3+1⁄4 in) broad; the scales are thin and flexible. The seeds are small,4–7 mm (3⁄16–1⁄4 in) long, and have a long slender wing15–22 mm (9⁄16–7⁄8 in) long.
The branches are borne in regularwhorls,[5] produced at the rate of one a year; this is pronounced in narrow, stand-grown trees, while open specimens may have a more rounded form with wide-reaching limbs. When mature, the tree has bark that appears to be cut into small, checkered units.[5]
It is related to the Eastern white pine (Pinus strobus),[5] differing from it in having larger cones, slightly longer-lasting leaves (2–3 years, rather than 1.5–2 years) with more prominentstomatal bands, and a somewhat denser and narrower habit.
The species occurs in humid areas of the mountains of theWestern United States andWestern Canada[5] such as theSierra Nevada, theCascade Range, theCoast Range, and the northernRocky Mountains. It can be found in elevations of 600 to 1,800 meters (2,000 to 5,900 ft) above sea level in eastern Washington and Oregon'sBlue Mountains[5] and 1,800 to 3,100 metres (5,900 to 10,200 ft) on the western face of the Sierra Nevada as far south as the headwaters of theKern River.[6][5] The tree often occurs in forests withfir andhemlock species, especially those which aretolerant of shade.[5] It benefits from disturbances that clear away competing species, including low fires that do not destroy all of its cone-protected seeds.[5] It is also well adapted to poor, rocky soils.[5]
Once abundant in northern Idaho, Western white pine's population was drastically affected from the late 19th century to the late 20th century by logging, wildfires,white pine blister rust, and abark beetle epidemic.[5] Since 1970, millions of Western white pine seedlings have been planted to make up for the losses.[5]
The white pine blister rust (Cronartium ribicola) is a fungus that was accidentally introduced fromEurope in 1909. TheUnited 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 thewhitebark pine outside ofCalifornia. Blister rust is less severe in California, and Western white and whitebark pines have survived there in great numbers.
Resistance to the blister rust is genetic; due to Western white pine's genetic variability, some individuals are relatively unaffected. The Forest Service has a program for locating and breeding rust-resistant Western white pine andsugar pine. Seedlings of these trees have been introduced into the wild.
The gum was reportedly chewed by Native Americans to treat coughs. Thepitch was used to fasten arrowheads and coat fishing and whaling instruments.[5] European colonists used both Western andEastern white pine as softwood lumber.[5] Both species are considered excellent for molding and carving.[5] First the Eastern and then the Western species were used in the building oftranscontinental railroads in the late 19th century.[5] In the early 20th century, white pine was used to build houses and make matches.[5]
Western white pine is widely grown as anornamental tree.[7]
