Pinus monticola Douglas ex D. Don:
Canada (North America)
United States (North America)

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Western white pine occurs only in western North America from British Columbia to California, eastwards to Utah and Montana.

Trees to 70m; trunk to 2.5m diam., straight; crown narrowly conic, becoming broad and flattened. Bark gray, distinctly platy, plates scaly. Branches nearly whorled, spreading-ascending; twigs slender, pale red-brown, rusty puberulent and slightly glandular (rarely glabrous), aging purple-brown or gray, smooth. Buds ellipsoid or cylindric, rust-colored, 0.4--0.5cm, slightly resinous. Leaves 5 per fascicle, spreading to ascending, persisting 3--4 years, 4--10cm ´ 0.7--1mm, straight, slightly twisted, pliant, blue-green, abaxial surface without evident stomatal lines, adaxial surfaces with evident stomatal lines, margins finely serrulate, apex broadly to narrowly acute; sheath 1--1.5cm, shed early. Pollen cones ellipsoid, 10--15mm, yellow. Seed cones maturing in 2 years, shedding seeds and falling soon thereafter, clustered, pendent, symmetric, lance-cylindric to ellipsoid-cylindric before opening, broadly lanceoloid to ellipsoid-cylindric when open, 10--25cm, creamy brown to yellowish, without purple or gray tints, resinous, stalks to 2cm; umbo terminal, depressed. Seeds compressed, broadly obovoid-deltoid; body 5--7mm, red-brown; wing 2--2.5cm. 2 n =24.

Pinus monticola is the most important western source for matchwood. Its wood lacks the sugary exudates seen in P . lambertiana . 

 Western white pine ( Pinus monticola ) is the state tree of Idaho.

Tree, Evergreen, Monoecious, Habit erect, Trees without or rarely having knees, Tree with bark rough or scaly, Young shoots 3-dimensional, Buds not resinous, Leaves needle-like, Leaves alternate, Needle-like leaf margins finely serrulate (use magnification or slide your finger along the leaf), Leaf apex acute, Leaves < 5 cm long, Leaves > 5 cm long, Leaves < 10 cm long, Leaves blue-green, Needle-like leaves triangular, Needle-like leaves twisted, Needle-like leaf habit erect, Needle-like leaves per fascicle mostly 5, Needle-like leaf sheath early deciduous, Twigs pubescent, Twigs viscid, Twigs not viscid, Twigs without peg-like projections or large fascicles after needles fall, Berry-like cones orange, Woody seed cones > 5 cm long, Seed cones bearing a scarlike umbo, Umbo with missing or very weak prickle, Umbo with obvious prickle, Bracts of seed cone included, Seeds red, Seeds brown, Seeds winged, Seeds unequally winged, Seed wings prominent, Seed wings equal to or broader than body.

Strobus monticola (Douglas ex D. Don) Rydberg

Systems

• Terrestrial

Comments: Western white pine occurs on a wide variety of sites from peat bogs to dry sandy soils and rocky ground, however it grows best in moist valleys or on slopes at near sea level to mid-elevations in mountains.

Montane moist forests, lowland fog forests; 0--3000m; Alta., B.C.; Calif., Idaho, Mont., Nev., Oreg., Wash.

Foodplant / parasite
subcortical pycnium of Cronartium ribicola parasitises stem of Pinus monticola
Remarks: season: 3-6
Other: major host/prey

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 6
Species: 6
Species With Barcodes: 1

Canada

Rounded National Status Rank: N4 - Apparently Secure

United States

Rounded National Status Rank: N4 - Apparently Secure

Rounded Global Status Rank: G4 - Apparently Secure

Reasons: Although still considered a fairly common species in many areas of its range, populations of western white pine are affected by white pine blister rust, different species of bark beetles, and susceptible to pole blight from extreme weather conditions. Population declines have been noted since early in the century with a massive dieback in the Pacific region in 1935-1936 triggered by highly anomalous winter weather (Auclair et al 1990). Continuing threats of disease and extremes of climate are still affecting populations, however breeding programs have produced strains that are 65% resistant to white pine blister rust (Griffth 1992). Others consider populations will continue to decline as blister rust infection spreads and intensifies (Tomback 2001).

Environmental Specificity: Broad. Generalist or community with all key requirements common.

Comments: Although western white pine is a fire-adapted early seral species, trees are susceptible to fire which can damage the cambium layer. This usually results in the death of young trees and the creation of fire scars in older trees. Fire scars can provide an opening for disease, such as butt-rot fungi, to infect a tree. However, fire also removes the humus layer, preparing a favourable seedbed and eliminates competing plants. Large amounts of humus also can cause tree death from heating of the roots (Griffith 1992). White pine blister rust (Cronartium ribicola), dwarf mistletoe (Arceuthobium spp.) and various species of bark beetles also are serious threats affecting populations. Pole blight, a xylem dysfunctional condition related to extreme climatic variation, results in massive cavitation, yellow foliage, crown dieback and the death of many trees. One critical factor with this specific condition was untimely soil frost and winter thaw-freeze cycles, whereas air pollution was determined not to relate to tree dieback for Pinus monticola (Auclair et al. 1990). Weather extremes with climate change may increase the occurrence of this condition in this species.

Biological Research Needs: Continued research for trees resistant to the white pine blister rust infection and the condition of pole blight caused by extreme climate events.