15 Mart 2013 Cuma

Washington State Tree

Washington State Tree

Western Hemlock (common name)
Tsuga heterophylla 
(scientific name)


The state of Washington was conspicuously lacking a state tree in 1946. This was pointed out by the Oregoniannewspaper, which used the situation to ridicule Washington. But the paper also did some good by suggesting western hemlock as a potential choice. In response, a Washington newspaper selected western red cedar as candidate for state tree. But Washington State Representative George Adams was a strong advocate of western hemlock. He predicted the tree would become "the backbone of this state's forest industry." His bill to make hemlock the state tree was passed in 1947.
Also called Pacific hemlock and west coast hemlock, western hemlock is a characteristic tree of the Pacific Northwest region, with a distribution that follows the coastline. A separate population occurs in the northern Rocky Mountains. It is not the largest-growing, nor the most important timber tree in the region. However, it is fast-growing and a colonizing species with a strong potential for tree farming. As an ornamental, western hemlock has performed well in cultivation in parts of Europe. In the eastern United States, conditions are less favorable, and its cultivation at the U.S. National Arboretum must be considered experimental.


Western hemlock is a conifer growing to 180 feet tall, with the growing tip often leaning or drooping. The flat needles are short, of variable length, and rounded at the tip. The tree's small cones have rounded scales.
Height: 100-200 ft (30-61 m)
Diameter: 2-9 ft (0.6-3 m)
Bark: young: scaly
mature: hard, furrowed
Seed Cones: small, pendulous, 14-30 mm long with 15-25 thin, flexible scales
Leaves: flat needles 0.25-0.9 in (6-22 mm) long, rounded at tips
Western hemlock typically reaches about 300 to 400 years of age. The maximum age recorded is in excess of 700 years.
Western hemlock thrives in the mild, humid climates of the Pacific Coast and northern Rocky Mountains where precipitation and fog are frequent. Because it is extremely shade-tolerant, it is found in many old-growth forests. In grassland regions with relatively dry growing seasons, western hemlock is confined primarily to northerly aspects, moist stream bottoms, or seepage sites. Mean annual temperatures where western hemlock commonly occurs range from 32 to 52°F (0-11°C).
Roosevelt elk and black-tailed deer browse western hemlock in coastal Oregon, Washington, and British Columbia. Black bear damage the bark at the bases of trees and larger saplings. Snowshoe hare and rabbit clip off the main stems of western hemlock seedlings. Mountain beaver clip the stems and lateral branches of seedlings and damage the bark at the base of saplings.
Old-growth western hemlock groupings provide hiding, nesting, and thermal cover for many wildlife species, including grizzly bear, northern flying squirrel, red tree vole, northern spotted owl, yellow-bellied sapsucker and northern three-toed woodpecker.
Western hemlock wood is recognized as an all-purpose raw material. It is one of the best pulpwoods for paper and paperboard products. It is the principal source of alpha cellulose fiber used in the manufacture of rayon, cellophane, and many plastics. Other uses are lumber for general construction, railway ties, mine timbers, and marine piling. The wood is suited also for interior finish, boxes and crates, kitchen cabinets, flooring, gutter stock, and veneer for plywood. The bark serves as a source of tannin for tanning leather.
Alaska Indians made coarse bread from the inner bark of western hemlock. By scraping slabs of removed bark, the edible cambium can be collected. The resulting shavings can be eaten immediately, or can be dried and pressed into cakes for preservation. Tender, new-growth needles can be chewed or made into a bitter tea, rich in vitamin C (similar to some other hemlock and pine species).
Some Coast Salish people used a red dye made from hemlock bark to color mountain goat wool and basket materials, and as a facial cosmetic and hair remover. Various tribes would use the bark to dye fishnets brown, making them invisible to fish. Black and yellow-orange dyes were also derived from the bark.
Western hemlock is generally a good cone and seed producer. Cones may form on open-grown trees that are less than 20 years old, but good cone crops usually do not occur until trees are between 25 and 30 years old. Western hemlock seeds have large wings, enabling them to be distributed over long distances.
Western hemlock will reproduce vegetatively by layering or cuttings.
Washington's state tree grows at low to mid elevations and in moist soils derived from all bedrock types. The tree is one of the most shade-tolerant species.
Western hemlock occurs in the Coast Ranges from Sonoma County, California, to the Kenai Peninsula in Alaska. Inland it occurs along the western and upper eastern slopes of the Cascade Range in Oregon and Washington. It also grows west of the Continental Divide in the northern Rocky Mountains of Montana and Idaho, and north to British Columbia and Alberta.
The elevational range of western hemlock is from sea level to 7,000 feet (2,130 m). On the coast, western hemlock develops best between sea level and 2,000 feet (610 m); in the Rocky Mountains, it develops best between 1,600 and 4,200 feet (490-1,280 m).
  • Hemlock was named after a European weed that has a similar smell. Tsuga is from the Japanese Tsu-ga, the elements for "tree" and "mother," and heterophylla is Greek for "different leaves."
  • Lewis and Clark were amazed by the gigantic size of Douglas-fir, Sitka spruce, and even the smaller western hemlock in the Pacific Northwest. In February 1806, Lewis wrote that western hemlock "rises to the height of 160 to 180 feet very commonly and is from 4 to 6 feet in diameter, very streight [sic] round and regularly tapering."
Disclaimer: The authors and publishers do not engage in the practice of medicine. Under no circumstances is this information intended as a medical recommendation.

Click to enlarge an image
State Tree
Western Hemlock
State tree
Western Hemlock Needles
State tree
Western Hemlock Cones
State tree
Western Hemlock Bark
State tree
Western Hemlock
Distribution Map (pdf)

Species:Tsuga heterophylla

Data Sources:
U.S. Forest Service
U.S. National Arboretum
U.S. Department of Agriculture
Author: World Trade Press

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