Abies concolor, the white fir, concolor fir, or Colorado fir, is a coniferous tree in the pine family Pinaceae. This tree is native to the mountains of western North America, including the Sierra Nevada and southern Rocky Mountains, and into the isolated mountain ranges of southern Arizona, New Mexico, and Northern Mexico. It naturally occurs at elevations between .

It is popular as an ornamental landscaping tree and as a Christmas tree.

Description

This large evergreen conifer grows best in the central Sierra Nevada of California, where the record specimen was recorded as tall and measured in diameter at breast height (dbh) in Yosemite National Park. The typical size of white fir ranges from tall and up to dbh. The largest specimens are found in the central Sierra Nevada, where the largest diameter recorded was found in Sierra National Forest at (1972); Abies concolor subsp. concolor (Rocky mountain white fir) rarely exceeds tall or dbh. Large (but not huge) trees in good soil range from tall and from dbh in California and southwestern Oregon and to tall and dbh in Arizona and New Mexico. The dead tree tops sometimes fork into new growth. The leaves are needle-like, flattened, long and wide by thick, green to glaucous blue-green above,

White fir can live over 300 years.

Subspecies

As treated here, there are two subspecies; these are also variously treated at either the lower rank of variety by some authors, or as distinct species by others:

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! Image !! Name !! Description !!Distribution

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|120px ||Abies concolor subsp. concolor — Colorado white fir or Rocky Mountain white fir||A smaller tree to tall, rarely . Foliage blue-green,

||In the United States, at altitudes of from the Cascades of Central Oregon south through California (Klamath Mountains, Sierra Nevada) to northern Baja California, Mexico.

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Botanical collection

White fir was first collected by Augustus Fendler on his expedition to the Santa Fe area of New Mexico in 1846–1847. Fendler's patron George Engelmann, a St. Louis area physician and botanist, then described the plant. This tree was first collected in California by William Lobb on his expedition to California of 1849–1853, after it was overlooked by David Douglas in his 1825–1827 expedition to the Pacific coast region.

The specific epithet concolor means "all one color".

Distribution

This tree is native to the mountains of western North America from the southern Cascade Range in Oregon, south throughout California and into the Sierra de San Pedro Mártir in northern Baja California, and south throughout the Colorado Plateau and southern Rocky Mountains in Utah and Colorado, and into the isolated mountain ranges of southern Arizona, New Mexico, and Northern Mexico. It naturally occurs between above sea level. White fir occupies a different niche than grand fir, including dryer and higher elevation sites, being more drought tolerant and having thicker, fire-resistant bark. White fir had been regarded as a pest in the past by those in the lumber industry, but this opinion has changed. White fir is now one of the most important of all commercial softwoods according to the Western Wood Products Association.

The white fir trait of retaining lower limbs creates an escape route for medium-to-small forest birds (such as spotted owl) from larger flying predators and provides a drip zone around the roots for collecting moisture. The retained limbs can become a fuel ladder that allows flames to climb up to the canopy. Giant Sequoia's cones release seeds when the heat of fire triggers them to open while the thick bark protects the inner cambium from fire damage.

This tree is host to fir mistletoe (Phoradendron pauciflorum) and fir dwarf mistletoe (Arceuthobium abietinum), two species of parasitic plant. It is attacked by many types of insects, such as the fir engraver (Scolytus ventralis).

Dependent species

Mature white fir–yellow pine forests support old-growth dependent wildlife species such as California spotted owl (Strix occidentalis occidentalis), Mount Pinos sooty grouse (Dendragapus fuliginosus howardi), and Pacific fisher (Pekania pennanti). The spotted owl and fisher utilize cavities in decadent large-diameter white fir for nesting and denning. The Mount Pinos sooty grouse requires large diameter trees for thermal cover and its winter diet consists of mostly white fir and yellow pine needles. This subspecies of sooty grouse has been extirpated along with a significant number of large diameter white fir from much of its range. Other subspecies of sooty grouse also utilize Douglas fir, which does not occur in the range of Mount Pinos sooty grouse. Squirrel also frequent the tree's branches.

Deer browse the foliage of this species and porcupines chew the bark. Songbirds, grouse, and various mammals eat the seeds.

Uses

White fir and grand fir were used by Native Americans for medicinal use involving powdered bark or pitch to treat tuberculosis or skin ailments. The Nlaka'pamux used the bark to cover lodges and make canoes. Branches were also used as bedding.

It is popular as a Christmas tree and for Christmas decoration owing to its soft needles, generally excellent needle retention and abundance. It is often marketed as concolor or white fir.

Cultivation

White fir is widely planted as an ornamental tree in parks and larger gardens, particularly some cultivars of subsp. concolor selected for very bright glaucous blue foliage, such as cv. 'Violacea'. The dwarf cultivar 'Compacta', growing to a maximum height and spread of , has gained the Royal Horticultural Society's Award of Garden Merit.

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Image:Abies_concolor_8076.jpg|A. concolor subsp. lowiana foliage upperside

Image:Abies_concolor_8065.jpg|A. concolor subsp. lowiana foliage underside

Image:Baby whitefir.jpg|A young sapling of subsp. lowiana on Mount Whitney

Image:White fir MN 2007.JPG|White fir in garden environment at Minnesota Landscape Arboretum

Image:Young Abies concolor.jpg|Small stand of young white firs on Cuyamaca Peak, California

Image:Toro Peak 537.jpg|White firs at Toro Peak, California

File:Arceuthobium abietinum 1.jpg|Foliage, with Arceuthobium abietinum infestation

</gallery>

References

Further reading

  • Jepson eFlora Treatment - Abies concolor
  • Gymnosperm Database: Abies concolor — (treated as varieties of one species).
  • Interactive Distribution Map of Abies concolor
  • USDA Plants Profile for Abies concolor (white fir)
  • Conifers Around the World: Abies concolor - Rocky Mountain White Fir.
  • Conifer Database