Forest Products

Commercial Species

 

Sitka Spruce (Picea sitchensis)

Sitka Spruce

The genus Picea is composed of about 30 species native to North America [12] and Eurasia [20]. The word picea comes from the ancient Latin name (pix, picis = pitch) of a pitchy pine, probably Scotch pine (Pinus sylvestris L.). The sitchensis is for Sitka Island (now Baranof Island) in southeastern Alaska.

General Wood Characteristics. The sapwood of Sitka spruce is a creamy white to light yellow, while the heartwood is pinkish-yellow to brown. The sapwood may be 3-6 inches wide or even wider in young trees. Because of the large size of the tree and its clear trunk, Sitka spruce produces a large proportion of wood with a clear, uniform texture and straight grain. It is moderately light in weight, moderately low in bending and compressive strength, moderately stiff, moderately soft, and moderately low in resistance to shock. On the basis of weight, it rates high in strength properties and can be obtained in clear, straight-grained pieces. It is classified as good in ability to stay in place, easy to work, very easy to glue, and takes paint and varnish well. It takes nails without splitting and holds them moderately well. It is a good serviceable construction wood but, like all spruces, is low in resistance to decay. It has moderately small shrinkage and is not difficult to kiln-dry. Thin panels of Sitka spruce are highly resonant, making them desirable for piano sounding boards and other instrument stock.

Working Properties. Sitka spruce can be easily worked when free of knots.

Durability. Sitka spruce is rated as slightly or nonresistant to heartwood decay.

The Tree. Sitka spruce trees normally reach heights of 160 feet, with diameters of 5 feet. A record tree reached 216 feet tall, with a diameter of 16.7 feet.

Distribution. Sitka spruce is the largest and most valuable tree species in Alaska. It is native to the Pacific coast region from southern Alaska (Kodiak Island and Cook Inlet), southeast through southeastern Alaska, western British Columbia, western Washington, western Oregon, and northwestern California.

Preservation. Sitka spruce is resistant to preservative treatments under pressure, but can be treated by a water diffusion process.

Uses. Alaska's Sitka spruce is a strong and serviceable wood. It excels in many characteristics, especially strength to weight, workability and pulping characteristics. Lumber, pulpwood, sounding boards for high quality pianos, guitar faces, ladders, components for experimental light aircraft, oars, planking, masts and spars for boats, and turbine blades. Sitka spruce slices well and is suitable for veneering. A clean finish is obtained in machining providing tools are sharp. It is an excellent pulpwood with a long fiber and good density. Sitka spruce is also perfectly acceptable as a structural wood. Stress data are known, span tables are published, and applicable grade rules are available.