ABLA

Abies lasiocarpa

sub-alpine fir

Pinaceae

USFS Plant Database

Flora of North America

The Basics

The only unique populations in this species come from coastal Alaska (A. S. Harris 1965; C. J. Heusser 1954). 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.

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 (R.S. Hunt and E.von Rudloff 1979). Abies lasiocarpa shares with A . procera a red periderm, crystals in the ray parenchyma (R.W. Kennedy et al. 1968), and reflexed tips of the bracts, features not shared with A . bifolia .

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 (W.H. 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 (W.H. Parker et al. 1979). (Flora of North America)

The genus Abies consists of about 40 species of evergreen trees found in the northern hemisphere. Nine species of Abies, including subalpine fir, are native to the United States. The currently accepted scientific name of subalpine fir is Abies lasiocarpa (Hook.) Nutt. Subalpine fir is widely distributed and exhibits geographic variation. (Plant Database)

Identification

Trees to 20m; trunk to 0.8m 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--3.1cm ´ 1.5--2mm, 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--4cm, dark purple, sessile, apex rounded; scales ca. 1.5 ´ 1.7cm, densely pubescent; bracts included (specimens with exserted, reflexed bracts are insect infested). Seeds 6 ´ 2mm, body brown; wing about 1.5 times as long as body, light brown; cotyledon number 4--5. 2 n =24. (Flora of North America)

Uses

Fir is used as lumber in building construction, boxes, crates, planing mill products, sashes, doors, frames, and food containers. It has not been widely used for pulpwood because of inaccessibility, but it can be pulped readily by the sulfate, sulfite, or groundwood processes. (Plant Database)

Threats

The only data available for yields of subalpine fir in managed stands are estimated from simulations for mixed Engelmann spruce-subalpine fir stands in the Rocky Mountains south of Idaho and Montana (7). These simulations show that periodic thinning to control stand density and maintain growth rates increases the yield and size of individual fir trees in these mixed stands. Furthermore, the growth rates for fir are similar to those for spruce early in the life of the stand. However, the fir component is likely to be greatly reduced by repeated thinnings, so that the stand at the time of final harvest will be almost pure Engelmann spruce.

Subalpine fir is susceptible to windthrow. Although, this tendency is generally attributed to a shallow root system, soil depth, drainage, and stand conditions influence the development of the root system. The kind and intensity of cutting and topographic exposure to wind also influence the likelihood of trees being windthrown.

Subalpine fir is attacked by several insects. In spruce-fir forests, the most important insect pests are the western spruce budwormÂ (Choristoneura occidentalis)Â and western balsam bark beetleÂ (Dryocoetes confusus).Â The silver fir beetleÂ (Pseudohylesinus sericeus)Â and the fir engraverÂ (Scolytus ventralis)Â may at times be destructive locally. In the Cascades, the balsam woolly adelgidÂ (Adelges piceae),Â introduced from Europe, is the most destructive insect pest. This insect has caused significant mortality to subalpine fir, virtually eliminating it from some stands in Oregon and southern Washington.

Subalpine fir bark is thin, especially on young trees, and lower limbs persist after death . These characteristics make subalpine fir susceptible to death or severe injury from fire. (Plant Database)

Reproduction

Flowering and Fruiting -Â Subalpine fir flowers are monoecious. Male flowers, usually abundant, are borne in pendulous clusters from the axils of the needles on the lower branchlets. Female flowers are fewer, borne erect and singly on the uppermost branchlets of the crown. Male flowers ripen, and pollen is wind-disseminated, during late spring and early summer. Cones are indigo blue when they open in mid-August to mid-October.Â

Seed Production and Dissemination -Â Subalpine fir may begin to produce cones when trees are 1.2 to 1.5 in (4 to 5 ft) tall and 20 years old, but under closed-forest conditions, seed production is not significant until trees are older and taller.Â

Seedling Development -Â Under natural conditions, fir seeds lie dormant under the snow and germinate the following spring. Although germination and early survival of subalpine fir are generally best on exposed mineral soil and moist humus, the species is less exacting in its seedbed requirements than most of its common associates. Subalpine fir has been observed to germinate and survive on a wide variety of other seedbed types including the undisturbed forest floor, undecomposed duff and litter, and decaying wood (9,15,19). Subalpine fir also invades and establishes on severe sites such as recent bums, lava flows, talus slopes, avalanche tracks, and climatically severe regions near timberline

Vegetative Reproduction -Â Subalpine fir frequently reproduces by layering where the species is a pioneer in developing forest cover on severe sites such as lava flows and talus slopes or near timberline. Under closed-forest conditions, reproduction by layering is of minor importance. (Plant Database)

Distribution

Coastal, subalpine coniferous forests; 1100--2300 m; B.C., Yukon; Alaska, Calif., Oreg., Wash. (Flora of North America)

Citation

USDA Plant Database http://plants.usda.gov/characteristics.html USDA, NRCS. 2016. The PLANTS Database (http://plants.usda.gov, 4 February 2016). National Plant Data Team, Greensboro, NC 27401-4901 USA.

Flora of North America http://www.efloras.org/flora_page.aspx?flora_id=1 Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 19+ vols. New York and Oxford.

Silvics of North America Burns, R.M., and B.H. Honkala. 1990. Silvics of North America (Volume 1: Conifers, Volume 2: Hardwoods). USDA Forest Service Agricultural Handbook 654.

Intermountain Herbarium http://intermountainbiota.org/portal/collections/harvestparams.php Consortium of Intermountain Herbaria. 2016. http//:intermountainbiota.org/portal/index.php. Accessed on February 04.

Burke Museum Plant Image Collection The plant image collection at the Burke Museum, University of Washington.

Jepson Manual http://ucjeps.berkeley.edu/eflora/ The Jepson Manual: Vascular Plants of California. B.G. Baldwin, D.H. Goldman, D.J. Keil, R. Patterson, T.J. Rosatti, and D.H. Wilken [editors]. 2012. 2nd edition, thoroughly revised and expanded. University of California Press, Berkeley, CA., hardcover; 1600 pages. ISBN-13: 978-0520253124.

USGS Plant Species Range Maps http://esp.cr.usgs.gov/data/little/ Critchfield, W.B., and Little, E.L., Jr., 1966, Geographic distribution of the pines of the world: U.S. Department of Agriculture Miscellaneous Publication 991, p. 1-97. Little, E.L., Jr., 1971-1978, Atlas of United States trees, volume 1,3,13,17, conifers and important hardwoods: U.S. Department of Agriculture Miscellaneous Publications.