A large coniferous evergreen tree growing to 50 - 70 m tall, exceptionally to 90 m tall, and with a trunk diameter of up to 5 m. It is by far the largest species of spruce, and the third tallest conifer species in the world (after Coast Redwood and Coast Douglas-fir). It acquires its name from the community of Sitka, Alaska.
The bark is thin and scaly, flaking off in small circular plates 5 - 20 cm across. The crown is broad conic in young trees, becoming cylindric in older trees; old trees may have no branches in the lowest 30 - 40 m. The leaves are stiff, sharp and needle-like, 15 - 25mm long, flattened in cross-section, dark glaucous blue-green above with two or three thin lines of stomata, and blue-white below with two dense bands of stomata.
The cones have thin, flexible scales 15 - 20 mm long; the bracts just above the scales are the longest of any spruce. They are green or reddish, maturing pale brown 5 - 7 months after pollination. The seeds are black, 3 mm long, with a slender, 7 - 9 mm long pale brown wing.
Sitka Spruce is a long-lived tree, with individuals over 700 years old known. Because it grows rapidly under favorable conditions, large size may not indicate exceptional age.
Sitka Spruce is of major importance in forestry for timber and paper production. It is used widely in piano, harp, violin, and guitar manufacture, as its high strength-to-weight ratio and regular, knot-free rings make it an excellent conductor of sound. The Steinway & Sons piano company is well known for using exclusively Sitka spruce soundboards in its pianos.
Outside of its native range, it is particularly valued for its fast growth on poor soils and exposed sites where few other trees can be grown successfully; in ideal conditions young trees may grow 1.5 m per year. It is naturalized in some parts of Ireland and Great Britain where it was introduced in 1831 (Mitchell, 1978) and New Zealand.
Newly grown tips of Sitka Spruce branches are used to flavour spruce beer and are boiled to make syrup.