14 Ocak 2013 Pazartesi

Alaska State Tree

Alaska State Tree

Sitka Spruce (common name)
Picea sitchensis
(scientific name)


The world's largest-growing spruce is the Sitka spruce, sometimes exceeding 200 feet in height. It can be found in the temperate rainforests of the Pacific Northwest. A tolerance for salt spray allows the spruce to grow right down to the seashore.
The Sitka spruce was designated as Alaska's state tree in 1962. Since the tree thrives only in the cool, moist, foggy climate of the Pacific Northwest, a substitute species is grown in the United States National Arboretum's National Grove of State Trees. The Alaska cedar represents Alaska in Washington, DC.


Sitka spruce is a wide spreading tree. It has rigid branches and drooping smaller branches called branchlets. Its bark is scaly and dark red-brown. Needles are green on the lower surface and white above.
Height: 72-200 ft (21.9-61.0 m)
Diameter: up to 16 ft (4.9 m)
Bark: scaly, dark red-brown
Seed: cylindrical, 1.5 to 3.5 in (3.8-8.9 cm) long
Leaves: 4-sided needles with sharp tips
Alaska's state tree is a native, long-lived, evergreen tree that can live for more than 800 years.
Sitka spruce grows in moist to swampy coastal areas. Because this species needs humidity to grow, the moist sea air and summer fogs of the north Pacific coasts make the perfect habitat for Sitka spruce. The tree follows the coastline from Alaska through Canada, then south to northern California. It grows in the company of redwoods, western hemlock, Alaska cedar, lodgepole pine, and western white pine. Sitka spruce can be found in dense groups where growth rates are among the highest in North America.
Sitka spruce forests provide habitat, in many cases critical habitat, for a large variety of mammals, birds, reptiles, and amphibians. Sitka spruce forests provide hiding and thermal cover for a large variety of mammals, including Sitka deer, elk, caribou, Alaskan brown bear, and mountain goat. Porcupines, rabbits, and hares browse the foliage. Sitka spruce provides good nesting and roosting habitat for birds such as the bald eagle and peregrine falcon.
The most important timber species in Alaska, Sitka spruce produces high-grade lumber for many uses and wood pulp for newsprint. The wood, with its high strength-to-weight ratio, is valuable for use as turbine blades for wind-driven electrical generators, masts for sailboats, ladders, oars, boats, and racing sculls. Sitka spruce's high resonant quality makes it valuable in the manufacture of
piano sounding boards and guitars. The wood from Sitka spruce is also used in saw timber, high-grade wood pulp, and plywood. It was formerly used in aircraft construction and has been used as the nose cones for missiles and spacecraft.
Native Americans have used Sitka spruce for various purposes. The roots can be woven to produce baskets and rain hats. The pitch was used for caulking canoes, for chewing, and for medicinal purposes. Pioneers split Sitka spruce into shakes for roofing and siding.
Sitka spruce has limited food value for humans, as the inner bark and young shoots may be eaten as emergency food. Tea can be made from the young shoots.
This tree reproduces both sexually and asexually. Sexual maturity varies from 20 to 40 years. Dispersal of seeds is moisture dependent; when the ripe cones dry, the seed is dispersed, and when the cones become wet again, they close.
The world's largest spruce reproduces asexually by layering. This usually takes place in moist areas or at timberline.
Sitka spruce occurs from shoreline to timberline in the northern portion of its range but is restricted to shoreline in the southern portion of its range. Sitka spruce grows best on sites with deep, moist, well-drained soils. It can tolerate the salty ocean spray of seaside dunes, headlands, and beaches, and the brackish water of bogs. Sitka spruce is limited to areas of high annual precipitation with cool, moist summers.
Sitka spruce grows in a narrow strip of land along the northern Pacific coast from southern Alaska through western British Columbia, Washington, Oregon, and northwestern California. It is also found in Hawaii and Yukon.
This species grows from sea level to timberline, 0-3,900 feet (0-1,189 m), in Alaska, with elevational limitations of 2,000 feet (600 m) in Washington and 1,500 feet (450 m) in Oregon and California.
  • Sitka spruce wood is light and flexible, and it was found to be ideal for use in airplane construction. The Mosquito bomber, used in World War II, and Howard Hughes's Spruce Goose were built using Sitka spruce from Alaska and British Columbia. 
  • The largest Sitka spruce in the United States is over 1,000 years old and 191 feet tall. It has a circumference of over 55 feet and is located in the Quinault Rain Forest, Washington.
  • Sitka spruce was widely employed medicinally by several native North American Indian tribes who used it especially for its antiseptic qualities in the treatment of lung complaints, sores, and wounds. It has been chewed in the treatment of throat problems, coughs, and colds. Sitka spruce resin was also used as a medicine for gonorrhea, syphilis, internal swelling, and toothaches. A concentrate of the roots has been used in the treatment of diarrhea.
Disclaimer: The authors and publisher do not engage in the practice of medicine. Under no circumstances is this information intended to be taken as a medical recommendation.

Click to enlarge an image
State Tree
Sitka Spruce
State tree
Sitka Spruce Needles
State tree
Sitka Spruce Cone
State tree
Sitka Spruce Bark
State tree
Sitka Spruce
Distribution Map (pdf)

Species:Picea sitchensis

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

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