Abies concolor

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).[4]

Abies concolor
White fir
Sierra Nevada white fir
in Yosemite National Park
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Pinaceae
Genus: Abies
Species:
A. concolor
Binomial name
Abies concolor
(Gordon) Lindley ex Hildebrand
Natural range of Abies concolor
green - A. concolor var. concolor
blue - A. concolor var. lowiana
Synonyms[2][3]
  • Abies concolor f. atroviolacea Cinovskis
  • Abies concolor subsp. lowiana (Gordon) A.E. Murray
  • Abies concolor var. bajacalifornica Silba
  • Abies concolor var. lowiana (Gordon) Lemmon
  • Abies concolor var. martinezii Silba
  • Abies grandis var. concolor (Gordon) A. Murray bis
  • Abies grandis var. lowiana (Gordon) Hoopes
  • Abies lasiocarpa var. pendula Carrière
  • Abies lowiana (Gordon) A. Murray bis
  • Abies lowiana var. pendula (Carrière) Fitschen
  • Abies lowiana var. viridula Debreczy & I. Rácz
  • Picea concolor Gordon & Glend.
  • Picea concolor var. violacea A.Murray bis
  • Picea grandis Newb.
  • Picea lowiana Gordon
  • Picea lowii Gordon
  • Picea parsonsiana Barron
  • Picea parsonsii Fowler
  • Pinus concolor Engelm. ex Parl.
  • Pinus concolor f. violacea (A.Murray bis) Voss
  • Pinus lowiana (Gordon) W.R. McNab

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

The specific epithet concolor means "all one color".[5]

Description

Size

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.[6] 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);[7] the west slope of the Sierra Nevada is also home to the tallest specimen on record, 78.8 m (257.5 ft) in height.[8] 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.[9]

Leaves and cones

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.[10]

Subspecies
Foliage and cones of subsp. concolor

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:

Abies concolor subsp. concolor
  • 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
  • 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)[11] 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.[12]

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).

Forest succession

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.[13] 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.[14]

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.[15] 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.[16]

Botanical collection

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.[17] 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.[18][19]

Ecology

This tree is host to fir mistletoe (Phoradendron pauciflorum), a parasitic plant. It is attacked by many types of insects, such as the fir engraver (Scolytus ventralis).[20]

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.[21] 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.[22] Squirrel also frequent the tree's branches.[23]

Deer browse the foliage of this species and porcupines chew the bark. Songbirds, grouse, and various mammals eat the seeds.[23][24]

Uses

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.[25]

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.[26]

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 2.5 m (8.2 ft), has gained the Royal Horticultural Society's Award of Garden Merit.[27][28]

References
  1. Farjon, A. (2013). "Abies concolor". IUCN Red List of Threatened Species. 2013: e.T42276A2969061. doi:10.2305/IUCN.UK.2013-1.RLTS.T42276A2969061.en.
  2. "Abies concolor". Tropicos. Missouri Botanical Garden.
  3. "Abies concolor". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew – via The Plant List.
  4. "Plant Fact Sheet: White Fir - Abies concolor" (PDF). Retrieved May 6, 2018.
  5. Harrison, Lorraine (2012). RHS Latin for Gardeners. United Kingdom: Mitchell Beazley. ISBN 978-1845337315.
  6. American Forestry Association. 1978. National register of big trees. American Forests 84(4):19-47
  7. American Forestry Association. 1978. National register of big trees. American Forests 84(4):19-47.
  8. Taylor, M. "New World Record for White Fir". Native Tree Society.
  9. Jones, John R. 1974. Silviculture of southwestern mixed conifers and aspen: the status of our knowledge. USDA Forest Service, Research Paper RM-122. Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 44 p.
  10. Hunt, Richard S. (1993). "Abies concolor". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). 2. New York and Oxford – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  11. Hunt, Richard S. (1993). "Abies lowiana". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). 2. New York and Oxford – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  12. "Abies lowiana". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 14 December 2017.
  13. http://www.fire.ca.gov/communications/downloads/fact_sheets/TheBenefitsofFire.pdf
  15. "Sequoiadendron giganteum".
  16. The Giant Sequoia of the Sierra Nevada
  17. Correspondence : Fendler (Augustus) and Engelmann (George) https://www.biodiversitylibrary.org/item/139836#page/9/mode/1up
  18. Jack Nisbet (2012). David Douglas, a Naturalist at Work: An Illustrated Exploration Across Two Centuries in the Pacific Northwest. Sasquatch books. p. 208. ISBN 9781570618307.
  19. Gordon, George, & Glendinning, Robert. Pinetum 155. 1858.
  20. Maloney P. E. & D. M. Rizzo. (2002). Pathogens and insects in a pristine forest ecosystem: the Sierra San Pedro Martir, Baja, Mexico. Canadian Journal of Forest Research 32:3 448-57.
  21. Sweitzer, Rick A.; Popescu, Viorel D.; Barrett, Reginald H.; Purcell, Kathryn L.; Thompson, Craig M. (2015). "Reproduction, abundance, and population growth for a fisher (Pekania pennanti) population in the Sierra National Forest, California". Journal of Mammalogy. 96 (4): 772–790. doi:10.1093/jmammal/gyv083.
  22. https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=10383&inline
  23. Peattie, Donald Culross (1953). A Natural History of Western Trees. New York: Bonanza Books. p. 196.
  24. Whitney, Stephen (1985). Western Forests (The Audubon Society Nature Guides). New York: Knopf. p. 360. ISBN 0-394-73127-1.
  25. Western Wood Products Association (WWPA)
  26. Christmas Tree Types Archived January 16, 2009, at the Wayback Machine
  27. "Abies concolor 'Compacta'". RHS. Retrieved 14 August 2019.
  28. "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 1. Retrieved 14 August 2019.

Further reading
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