Kingdom: Plantae

Phylum: Coniferophyta -- conifers

Class: Pinopsida

Order: Pinales

Family: Pinaceae -- pine

Common Name: tamarack, western larch

Species Code: LAOC

Origin: Native to foothills and low mountains from southern British Columbia, the Cascade Mountains of Washington and Oregon, eastward to northern Idaho and western Montana, and south to the Blue and Wallowa Mountains of southeast Washington and northeast Oregon.

Rare: no

Form: tree, to 80 meters tall; bark thick, deeply furrowed and flaking; young twigs glabrous to hairy; branches generally horizontal; with dark brown spherical buds, usually puberulent.

Duration: perennial

Longevity: long

Habitat Type: forest

Wetland Indicator Status: FACU+

Leaves: deciduous, needles 15-30 per spur, pale green, stiff, 25-45 mm long, triangular in cross-section, lower surface ridged in center.

Fruit: male and female cones (stroboli) borne terminally on short spur branches, often adjacent; staminate cones yellow, about 1 cm long; ovulate cones 2.5-3.5 cm long, yellowish to reddish-brown when young, brown on aging, maturing the first season; seeds about 3 mm long with the wings 6-7 mm long, brown to reddish, cotyledons usually 5-6.

Mature height: 150-180 (200) feet

Anthesis: spring

Characteristics:
Reproduces sexually by seed.
221,500 seeds/lb (Hassell et al 1996).
143,040 seeds/lb (USDA NRCS Plants Database 2009).
n=12 (Hitchcock et al 1969, Flora of North America Editorial Committee 1993).
Wind pollinated.
Plants are monoecious.
Larix occidentalis is unique among local conifers in that it sheds its needles every fall.
Seeds are windborne, at least for short distances.
A valuable timber species and for firewood. Native peoples used various plant parts for medicinal purposes and some used the dried sap for food.
Twigs are occasionally browsed by deer. Grouse eat the needles (Petrides 1998).
Provides cover and shelter for wildlife.
May live as long as 900 years (Petrides 1998).

Comments: Very shade intolerant.

Sun requirement: full sun

Soil moisture: mesic

Precipitation: 13-50 inches (USDA NRCS PLANTS Database 2009).

Fire: The thick bark and the tendency to self-prune the lower limbs make the species fire resistant (Petrides 1998, Scher 2002).
Recolonizes burned areas from seed. Eventually replaced by shade tolerant species in the absence of fire (Scher 2002).

Sowing time: fall

Transplant time: spring

Stratification: 30-45 days cold moist

Seed harvest: difficult

Seed first harvest: 25 years (Scher 2002)

Seed cleaning: medium difficulty

Planting duration: long

Seed shatter: low

Seed size: medium

Seed harvest date: September, October

Herbaria: Specimen data and digital resources from The Consortium of Pacific Northwest Herbaria

Key words: native upland forest tree

Propagation:
3 protocols in the Native Plant Network
University of Kentucky
J. Herbert Stone Nursery, Oregon
Glacier National Park, Montana

Other Propagation Information:
Reproduces sexually by seed.

Notes: An excellent landscape tree (Idaho Native Plant Society 1999).

References:
Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 7+ vols. New York and Oxford. Oxford University Press. Online at http://www.fna.org/FNA/

Hassell, Wendell, W. Rocky Beavers, Steve Ouellette, and Thomas Mitchell. 1996. Seeding Rate Statistics for Native and Introduced Species. US Department of Interior and US Department of Agriculture, NRCS. Denver, CO.

Hitchcock, C. Leo, Arthur Cronquist, Marion Ownbey, and J.W. Thompson. 1969. Vascular Plants of the Pacific Northwest. University of Washington Press. Seattle, WA. 5 vol.

Idaho Native Plant Society. 1999. Native Plants of Northern Idaho for Landscaping and Restoration. INPS White Pine Chapter. Moscow, ID. Online at http://www.idahonativeplants.org/guides/NorthIdahoGuide.aspx

Petrides, George A. 1998. A Field Guide to Western Trees. Peterson Field Guide Series. Houghton Mifflin Co. Boston, MA.

Scher, Janette S. 2002. Larix occidentalis. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2009, October 23].

USDA NRCS. 2009. The PLANTS Database (http://plants.usda.gov, 22 October 2009). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

Links:
Plant Profile from the USDA PLANTS Database
Species account from the Fire Effects Information System
Species description from Flora of North America
Species information from the University of Washington Herbarium