Abies lasiocarpa

(Hooker) Nuttall 1849

Common names

Subalpine fir, alpine fir, balsam fir, white fir, mountain balsam fir (Peattie 1950), sapin concolore (Hunt 1993).

Taxonomic notes

Syn: Pinus lasiocarpa Hooker 1838. See also Abies bifolia, which includes most of the populations formerly described as A. lasiocarpa (Hunt 1993).

A. lasiocarpa formerly included the Rocky Mountain populations now segregated as A. bifolia. Also see A. bifolia for remarks on the variety, arizonica.

Through central British Columbia and northern Washington, Abies lasiocarpa introgresses with A.bifolia. These trees may have morphologic features resembling either species and may have intermediate terpene patterns; they are best classified as interior subalpine fir (A. bifolia × lasiocarpa). At the southern end of its range, A. lasiocarpa possibly hybridizes with A. procera. Abies lasiocarpa shares with A. procera a red periderm, crystals in the ray parenchyma, and reflexed tips of the bracts, features not shared with A. bifolia (Hunt 1993).

The only unique populations in this species come from coastal Alaska (Heusser 1954, Harris 1965). They are found at lower elevations (0-900 m) and appear to be isolated with no reported introgression between them and the coastal mountain populations. The population on the Prince of Wales Island has distinct terpene patterns and needs morphological and developmental studies to see if these patterns contrast with neighboring populations (Hunt 1993).

Description

"Trees to 20 m; trunk to 80 cm diam.; crown spirelike. Bark gray, thin, smooth, furrowed in age. Branches stiff, straight; twigs opposite to whorled, greenish gray to light brown, bark splitting as early as 2 years to reveal red-brown layer, somewhat pubescent; fresh leaf scars with red periderm. Buds hidden by leaves or exposed, tan to dark brown, nearly globose, small, resinous, apex rounded; basal scales short, broad, equilaterally triangular, glabrous or with a few trichomes at base, not resinous, margins crenate to dentate, apex sharp-pointed. Leaves 1.8-3.1 cm × 1.5-2 mm, spiraled, turned upward, flexible; cross section flat, prominently grooved adaxially; odor sharp (ß-phellandrene); abaxial surface with 4-5 stomatal rows on each side of midrib; adaxial surface bluish green, very glaucous, with 4-6 stomatal rows at midleaf, rows usually continuous to leaf base; apex prominently or weakly notched to rounded; resin canals large, ± median, away from margins and midway between abaxial and adaxial epidermal layers. Pollen cones at pollination ± purple to purplish green. Seed cones cylindric, 6-12 × 2-4 cm, dark purple, sessile, apex rounded; scales ca. 1.5 × 1.7 cm, densely pubescent; bracts included (specimens with exserted, reflexed bracts are insect infested). Seeds 6 × 2 mm, body brown; wing about 1.5 times as long as body, light brown; cotyledons 4-5. 2n=24" (Hunt 1993).

Range

Canada: S Yukon and the Coast Range of British Columbia. USA: Coast ranges of SE Alaska, the Olympics of Washington, the Cascades of Washington and Oregon, and the Trinity Mountains of California. Typically found at 1100-2300 m elevation in coastal subalpine conifer forests (Peattie 1950). It is found growing to the alpine treeline in most of its range (Little 1980). Common associates include Abies amabilis, Pinus albicaulis and Tsuga mertensiana. See also Thompson et al. (1999).

The lower photo at left shows a tree clump comprised exclusively of Abies lasiocarpa. Tree clumps such as these are common in subalpine areas and are the common feature of a phytogeographic type, the forest-tundra parkland. Many subalpine species occur in forest-tundra parkland, but it is an especially common setting for subalpine fir (including Abies lasiocarpa and Abies bifolia). Typically such parklands form in settings where heavy winter snowfall shortens the growing season and lowers soil temperature to the point where tree seedling establishment is impeded. Isolated trees may establish in such settings during intervals of warmer and/or drier climate, or sometimes they represent trees of other species. Solar radiation reflected from the isolated trees causes the snow around them to melt earlier in the season, creating a microsite with marginally better seedling establishment conditions. Over time a forest of seedlings grows up around the pioneer tree, forming a tree clump. Such clumps may persist as discrete units on the landscape for a thousand years or more until eradicated by fire or disease, or until climate and microsite changes transform the site into forest -- or tundra. See also Arno and Hammerly (1984).

Big tree

Largest: Diameter 204 cm, height 38.1 m, crown spread 8 m in 1992, at Cream Lake in Olympic National Park, WA (Van Pelt 1996).

Tallest: Diameter 107 cm, height 52 m, crown spread 7 m in 1988; on the Icicle Creek Trail in the Alpine Lakes Wilderness of WA (Van Pelt 1996).

Oldest

A tree in Yukon Territory with a crossdated age of 501 rings, reported by Luckman (2003; cited by RMTRR 2006).

Dendrochronology

Ethnobotany

Observations

Very common in the subalpine zone of mountains throughout its range. It occurrences in Olympic and Mount Rainier National Parks are particularly noteworthy, having been the subject of a numerous ecological studies of the trees' population dynamics, response to fire, habitat value, etc. (see notes and citations in Arno and Hammerly (1984).

Remarks

"Abies lasiocarpa usually exists in small stands at high elevations and is not often observed. Its differences in comparison to A.bifolia have prompted studies (Parker et al. 1979) to see if it is A.bifolia introgressed with the sympatric A. amabilis. Abies lasiocarpa and A.amabilis, however, are separated by many morphologic features, and no hybrids have been found" (Hunt 1993).

Citations

Arno, Stephen F. and Ramona Hammerly. 1984. Timberline: mountain and arctic forest frontiers. Seattle: The Mountaineers.

Harris, A.S. 1965. Subalpine fir [Abies lasiocarpa(Hook.) Nutt.] on Harris Ridge near Hollis, Prince of Wales Island, Alaska. Northwest Science 39:123-128.

Heusser, C.J. 1954. Alpine fir at Taku glacier, Alaska, with notes on its post glacial migration to the territory. Bulletin of the Torrey Botanical Club 81:83-86.

Luckman, B.H. 2003. Assessment of present, past and future climate variability in the Americas from treeline environments. IAI CRN03 Annual Report 2003.

See also

Burns and Honkala 1990.

Farjon 1990.

Lanner 1983.

Lanner 1999.

Liu 1971.

MacKinnon et al. 1992.

FEIS database.

Vidakovic 1991.

Zavarin, E., K.Snajberk, T.Reichert, and Tsien E. 1970. On the geographic variability of the monoterpenes from the cortical blister oleoresin of Abies lasiocarpa. Phytochemistry 9:377-395.