|Sierra Nevada white fir |
in Yosemite National Park
|Natural range of Abies concolor
green - A. concolor var. concolor
blue - A. concolor var. lowiana
|Synonyms  |
Abies concolor, the white fir, is a coniferous tree in the pine family Pinaceae. 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; east through parts of southern Idaho, to Wyoming; 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. White fir live over 300-years and naturally occur at an elevation between 900–3,400 m (2,950–11,200 ft). 
It is popular as an ornamental landscaping tree and as a Christmas tree.
The specific epithet concolor means "all one color". 
This large evergreen coniferous tree grows best in the central Sierra Nevada of California, where the record specimen was recorded as 74.9 m (246 ft) tall and measured 4.6 m (183 in) in diameter at breast height (dbh) in Yosemite National Park.  The typical size of white fir ranges from 25–60 m (80–195 ft) tall and up to 2.7 m dbh (8.9 ft). The largest specimens are found in the central Sierra Nevada, where the largest diameter recorded was found in Sierra National Forest at 58.5 x 8.5 m (192′ x 27′ 11″) (1972).  Rocky mountain white fir rarely exceed 38 m (125 ft) tall or 0.9 m (3 ft) dbh. Large but not huge trees, in good soil, range from 40 to 60 m (131 to 195 ft) tall and from 99 to 165 cm (39 to 65 in) dbh in California and southwestern Oregon and to 41 m (134 ft) tall and 124 cm (49 in) dbh in Arizona and New Mexico. 
The leaves are needle-like, flattened, 2.5–6 cm (1–2 3⁄8 in) long and 2 mm (3⁄32 in) wide by 0.5–1 mm (1⁄64–3⁄64 in) thick, green to glaucous blue-green above, and with two glaucous blue-white bands of stomatal bloom below, and slightly notched to bluntly pointed at the tip. The leaf arrangement is spiral on the shoot, but with each leaf variably twisted at the base so they all lie in either two more-or-less flat ranks on either side of the shoot, or upswept across the top of the shoot but not below the shoot.
The cones are 6–12 cm (2 1⁄4–4 3⁄4 in) long and 4–4.5 cm (1 5⁄8–1 3⁄4 in) broad, green or purple ripening pale brown, with about 100–150 scales; the scale bracts are short, and hidden in the closed cone. The winged seeds are released when the cones disintegrate at maturity about 6 months after pollination. 
- Abies concolor subsp. concolor — Colorado white fir or Rocky Mountains white fir. In the United States, at altitudes of 1,700–3,400 m (5,600–11,200 ft) in the Rocky Mountains from southern Idaho, south through Utah and Colorado, to New Mexico and Arizona, and on the higher Great Basin mountains of Nevada and extreme southeastern California, and a short distance into northern Sonora, Mexico. A smaller tree to 25–35 m (80–115 ft) tall, rarely 45 m (150 ft). Foliage strongly upcurved to erect on all except weak shaded shoots in the lower crown; leaves mostly 3.5–6 cm (1 3⁄8–2 3⁄8 in), and strongly glaucous on the upper side with numerous stomata. Tolerates winter temperatures down to about −40 °C (−40 °F).
- Abies concolor subsp. lowiana ( syn. Abies lowiana) — Low's white fir or Sierra Nevada white fir. In the United States, at altitudes of 900–2,300 m (3,000–7,500 ft)  from the Cascades of central Oregon south through California ( Klamath Mountains, Sierra Nevada) to northern Baja California, Mexico. A larger tree to 40–60 m (130–195 ft) tall. Foliage flattened on lower crown shoots, the leaves often raised above the shoot on upper crown shoots but not often strongly upcurved; leaves mostly 2.5–5 cm (1–2 in), and only weakly glaucous on the upper side with few or no stomata. Tolerates winter temperatures down to about −30 °C (−22 °F). The United States Department of Agriculture plants database describes this subspecies as the full species Sierra white fir - Abies lowiana (Gordon & Glend.) A. Murray bis. 
White fir is very closely related to grand fir (Abies grandis), with subspecies lowiana being particularly similar to the interior variety of grand fir A. grandis var. idahoensis, intergrading with it where they meet in the Cascades of central Oregon. To the south in Mexico, it is replaced by further close relatives, Durango fir (A. durangensis) and Mexican fir (A. mexicana).
White fir is a shade tolerant, climax species, which means the forest has reached complex maturity in forest succession in western coniferous forests of the United States. White fir and yellow pine ( ponderosa pine/ Jeffrey pine) have co-existed for millennia in old growth forests throughout their range. In the presence of logging of large diameter trees and exclusion of cleansing wildfires, young trees have become abundant over the past two centuries.  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 ( spotted owl) from larger flying predators and provides a drip zone around the roots for collecting moisture. The retained limbs can become a fire ladder that allow flames to climb up to the canopy. Limbing-up white fir, instead of removing medium to large diameter trees, in areas where the public is more likely to start fires can help keep other trees and specifically giant sequoia from experiencing canopy fire. Recent concern for sequoia groves has caused agencies to call for removal of white fir in the Sierra Nevada. While sequoia seedlings and young saplings are highly susceptible to mortality or serious injury by fire; mature sequoias are fire adapted with: fire resistant bark, elevated canopies, self-pruning lower branches, latent buds, and serotinous cones. The sequoia ecosystem is incomplete without the mixed pine/fir and oak that make up the mid and understory.  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. 
White fir was first collected by Augustus Fendler on his expedition to the Santa Fe area of New Mexico in 1846–1847. Fender'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 1825-27 expedition to the Pacific coast region.  
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. 
White fir is a preferred construction species because of its nail-holding ability, lightness in weight, and resistance to split, twist, and pitch. It is straight-grained, non-resinous, fine-textured, stiff, and strong. 
White fir 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. 
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 2.5 m (8.2 ft), has gained the Royal Horticultural Society's Award of Garden Merit.  
A young sapling of subsp. lowiana on Mount Whitney
White fir in garden environment at Minnesota Landscape Arboretum
Small stand of young white firs on Cuyamaca Peak California
White firs at Toro Peak, CA.
Foliage, with Arceuthobium abietinum infestation
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- The Giant Sequoia of the Sierra Nevada
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- Western Wood Products Association (WWPA)
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