Subalpine Fir

''Abies lasiocarpa'', the subalpine fir or Rocky Mountain fir, is a western North American fir tree.

Description

''Abies lasiocarpa'' is a medium-sized evergreen conifer with a very narrow conic crown, growing to tall, exceptionally , with a trunk up to thick, exceptionally . The bark on young trees is smooth, gray, and with resin blisters, becoming rough and fissured or scaly on old trees. The lowest branches can be observed growing above ground level. The leaves are flat and needle-like, long, glaucous green above with a broad stripe of stomata, and two blue-white stomatal bands below; the fresh leaf scars are reddish (tan on the inland variety). They are arranged spirally on the shoot, but with the leaf bases twisted to be arranged to the sides of and above the shoot, with few or none below the shoot. The cones are erect, long, dark purple with fine yellow-brown pubescence, ripening brown and disintegrating to release the winged seeds in early fall.

Taxonomy

There are two or three taxa in subalpine fir, treated very differently by different authors:
*The Coast Range subalpine fir (''Abies lasiocarpa'') in the narrow sense, is the typical form of the species, occurring in the Pacific Coast Ranges, the Olympic Mountains and the Cascade Range from Southeast Alaska (Panhandle mountains) south to California.
*The Rocky Mountains subalpine fir is very closely related and of disputed status, being variously treated as a distinct species ''Abies bifolia'', as a variety of Coast Range subalpine fir ''Abies lasiocarpa'' var. ''bifolia'', or not distinguished from typical ''A. lasiocarpa'' at all. It occurs in the Rocky Mountains from Southeast Alaska (eastern Alaska Range) south to Colorado. It differs primarily in the chemical composition of its resin, microscopic features, and in the fresh leaf scars being yellow-brown, not reddish. The ''Flora of North America'' treats it as a distinct species, while the United States Department of Agriculture (USDA) includes it within ''A. lasiocarpa'' without distinction.
*The corkbark fir ''Abies lasiocarpa'' var. ''arizonica'' occurs in Arizona and New Mexico. It differs in thicker, corky bark and more strongly glaucous foliage. In resin composition it is closer to ''A. bifolia'' than to typical ''A. lasiocarpa'', though the combination "Abies bifolia var. arizonica" has not been formally published. The ''Flora of North America'' includes it within ''A. bifolia'' without distinction; the USDA treats it as a distinct variety of ''A. lasiocarpa''.

Distribution

The species is native to the mountains of Yukon, British Columbia and western Alberta in Western Canada; and to Southeast Alaska, Washington, Oregon, Idaho, Western Montana, Wyoming, Utah, Colorado, New Mexico, Arizona, northeastern Nevada, and the Trinity Alps of the Klamath Mountains in northwestern California in the Western United States.

It occurs at high altitudes, commonly found at and immediately below the tree line. It can be found at elevations of in the north of the range (rarely down to sea level in the far north), to in the south of the range. West of the Cascade ridge, it can be found at elevations of , while further east (particularly in Western Montana) it can be found from .

Ecology

Annual precipitation ranges from in coastal mountain sites to only inland. Snow gathered on the branches helps protect them from wind and heat. Firs in general act as a snow fence, leading to the creation of meadows through extra moisture accumulation.

The tree is highly shade tolerant, but very vulnerable to fire, short-lived, and slow-growing. Despite having weaker wood than some of its timberline associates, it can survive by its ability to adapt (growing in a ''krummholz'' form) and reproduce via layering in clusters at high elevations. At timberline, a single tree can leave behind a ring of trees (an 'atoll') via layering. The species has benefited from wildfire suppression in more recent years.

Various animals, including mountain goats, take shelter in subalpine fir clusters and ''krummholz''. The bark is browsed by game animals and its leaves are eaten by grouse. Songbirds, Richardson's grouse, Cascade pine squirrels, and other mammals consume the seeds. It is host to pathogenic fungi such as the species '' Delphinella balsameae''.

Uses

Native Americans used the leaves as deodorant and burned them as incense or medicinal vapor. Powdered bark and other components were used in solutions to treat colds. Resin was used to dress wounds or chewed as gum. The tree boughs were used for bedding. Some Plateau Indian tribes drank or washed in a subalpine fir boil for purification or to make their hair grow.

The light wood is considered poor quality, but sometimes used for wood pulp, general structural purposes and paper manufacture. It is also a popular Christmas tree. It is a popular ornamental tree for parks and large gardens, grown for its strongly glaucous-blue foliage. It can also function as a bonsai. The cultivar ''Abies lasiocarpa'' var. ''arizonica'' 'Compacta' is suitable for smaller gardens, growing as a shrub to tall by broad. In the UK It has gained the Royal Horticultural Society's Award of Garden Merit.

The largest-known specimen, measuring thick and tall, had a small door in its trunk and a storage space, which the film crew of the Disney-produced documentary '' The Olympic Elk'' (1952) used to store equipment.

HurricaneRidge 7392t.jpg, Specimen in Olympic National Park in mid-September
Abies lasiocarpa 7458.jpg, Specimen in Mount Rainier National Park in late September

References

External links

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Gymnosperm Database: ''Abies lasiocarpa''Flora of North America: ''Abies lasiocarpa''Flora of North America: ''Abies bifolia''Interactive Distribution Map of ''Abies lasiocarpa''

{{Authority control

lasiocarpa
Flora of the Northwestern United States
Flora of Alaska
Flora of Alberta
Flora of Arizona
Flora of British Columbia
Flora of California
Flora of Nevada
Flora of New Mexico
Flora of the Northwest Territories
Flora of Yukon
Taxa named by Thomas Nuttall
Trees of Northern America