Limber Pine

The very durable Limber Pine is a species of high-elevation, evergreen coniferous trees typically found in the mountainous regions of the Western US, Canada, and Mexico. These trees have an initial pyramidal structure but at maturity, their crown becomes more rounded, while those limber pines growing in high alpine sites are relatively shorter with a shrubby and twisted form.

Scientific Classification

Kingdom	Plantae
Division	Pinophyta
Class	Pinopsida
Order	Pinales
Family	Pinaceae
Genus	Pinus
Subgenus	Strobus
Scientific Name	Pinus flexilis

Quick Information

Other Names	Limbertwig, pino (in Spanish), pin blanc de l’ouest (in French), Rocky Mountain pine
Other Related Species	Pinus albicaulis (Whitebark pine), Pinus monticola (Western white pine)
Size	10-25 m (33-82 ft) tall, trunk diameter of 60-200 cm
Leaves	Occur in groups of five needles, clustered at the tip of the twigs, 3-9 cm long, dark green or bluish green, rows of white stomatal lines cover the entire length, persist 5-6 years
Cones	Large, cylindrical; 8-20 cm long, yellowish-brown, thickened and sticky scales at the tip; nut-like, wingless seeds
Bark	Nearly smooth, light gray turning into dark brown, ridges and scaly plates developing with age; twigs are smooth, stout, and flexible, silvery white to grayish
Distribution/Range	Rocky Mountains, Alberta, British Columbia (in Canada); New Mexico, Texas, SE California, Northern Arizona, Nevada, Utah (in the US); isolated localities in Coahuila, Chihuahua, Sonora, and Nuevo Leon (in Mexico)
Hardiness Zones	4-7
Growth Rate	Slow
Lifespan	Long-lived species, some trees live for over 1000 years
Growing Conditions	Winter Conditions: Grows in regions with very cold and dry winters, tolerates rapid temperature fluctuations Summer Conditions: Warm and slightly humid summers as found in places with Continental and Pacific maritime climates Rain: Low to moderate amount of precipitation, especially during its growing season Sunlight: Partial or full sun Soil Requirements: Sand, loam, alkaline, clay, acidic, well-drained, moist
Problems/Diseases/Pests	Butt rot, red-brown butt rot, red ring rot, brown cubical rot; white-pine blister rust, lodgepole-pine dwarf mistletoe, limber-pine dwarf mistletoe, and Douglas-fir dwarf mistletoe; insects such as budworm, cone moth, wooly aphid, and mountain pine beetle attack these trees
Flowering/Fruiting	Male strobili are formed during the spring, after which the female strobili emerge; pollen grains are shed during June-July, fertilization occurs in the spring/early summer, seeds are dispersed between September and October
Seed production	Every 2-4 years, seeds are borne from 20-40 years of age
Wildlife Value	Clark’s nutcrackers and red squirrels feed on limber pine seeds and cache them for future use; American black bears also raid these caches for pine “nuts”; the trees are used as nesting sites by mountain bluebirds, squirrels, and Northern Flickers
Cultivars	Pinus flexilis cv. ‘Columnaris’ inus flexilis cv. ‘Glauca’ Pinus flexilis cv. ‘Glauca Pendula’ Pinus flexilis cv. ‘Glenmore Dwarf’ Pinus flexilis cv. ‘Nana’ Pinus flexilis cv. ‘Pendula’ Pinus flexilis cv. ‘Vanderwolf’s Pyramid’
Uses	Vanderwolf Pine is used as an ornamental tree in gardening; southwestern white pine in landscaping; makes a good Christmas tree
Identification	Some isolated populations are found at lower elevations, its large woody cones open when dry; its long needles do not have resin dots
IUCN Conservation Status	Least Concern

Interesting Facts

• The oldest known limber pine tree, found in Eagle Cap Wilderness in the US state of Oregon, is believed to be more than 2000 years old. Another limber pine named “Twister” in the Alta Ski Area, Utah, is more than 1700 years old.
• These trees are highly adaptable to harsh conditions and are tolerant to drought. Some horticulturists believe that the limber pine can grow under unfavorable cultural conditions including compacted clay soil.
• The limber pine’s scientific name, as well as the common name, refers to its flexible wood and twigs, a great adaptation that helps in dealing with heavy ice and snowpack.

References:

1. https://en.wikipedia.org/wiki/Pinus_flexilis
2. https://extension.usu.edu/rangeplants/shrubs-and-trees/limber-pine
3. https://www.for.gov.bc.ca/hfd/library/documents/treebook/limberpine.htm
4. https://www.iucnredlist.org/species/42363/2975338
5. https://extension.usu.edu/rangeplants/shrubs-and-trees/limber-pine