Common Name(s): Sitka Spruce
Picea sitchensis
DISTRIBUTION
Northwestern North America
TREE SIZE
130-160 ft (40-50 m) tall, 4-6 ft (1.2-1.8 m) trunk diameter
AVERAGE DRIED WEIGHT
27 lbs/ft 3 (425 kg/m 3 )
SPECIFIC GRAVITY (Basic, 12% MC)
.36, .42
JANKA HARDNESS
510 lb f (2,270 N)
MODULUS OF RUPTURE
10,150 lb f /in 2 (70.0 MPa)
ELASTIC MODULUS
1,600,000 lb f /in 2 (11.03 GPa)
CRUSHING STRENGTH
5,550 lb f /in 2 (38.2 MPa)
SHRINKAGE
Radial: 4.3%, Tangential: 7.5%,
VOLUMETRIC
11.5%, T/R Ratio: 1.7
COLOR/APPEARANCE
Ranges from cream/white to yellow; heartwood can also exhibit a subtle pinkish red hue in some instances. Sapwood not clearly demarcated from heartwood. Some pieces can exhibit a special grain pattern called bearclaw—vaguely resembling the scratches of a bear’s claws.
GRAIN/TEXTURE
Sitka Spruce has a fine, even texture, and a consistently straight grain.
ENDGRAIN
Medium sized resin canals (larger than other spruce), sparse to numerous and variable in distribution; solitary or in tangential groups of several; earlywood to latewood transition gradual, color contrast medium; tracheid diameter medium-large.
ROT RESISTENCE
Heartwood is rated as being slightly resistant to non-resistant to decay.
WORKABILITY
Easy to work, as long as there are no knots present. Glues and finishes well, though it can give poor (blotchy and inconsistent) results when being stained due to its closed pore structure. A sanding sealer, gel stain, or toner is recommended when coloring Spruce.
ODOR
No characteristic odor.
ALLERGIES/TOXICITY
Although severe reactions are quite uncommon, Spruce in the Picea genus has been reported as a sensitizer. Usually most common reactions simply include skin irritation and/or respiratory disorders. See the articles Wood Allergies and Toxicity and Wood Dust Safety for more information.
PRICING/AVAILABILITY
Construction grade spruce is cheap and easy to find. However, old growth and/or quartersawn clear pieces—free from knots—can be more expensive. Quartersawn billets of instrument-grade Sitka Spruce can easily exceed the cost of most all domestic hardwoods in terms of per board-foot cost.
SUSTAINABILITY
This wood species is not listed in the CITES Appendices, and is reported by the IUCN as being a species of least concern.
COMMON USES
Lumber, boxes/crates, furniture, millwork, aircraft components, musical instrument soundboards, boatbuilding (masts and spars), wind turbine blades, and virtually any application where a wood material with a good strength-to- weight ratio is needed.
COMMENTS
Sitka Spruce has an outstanding stiffness-to- weight ratio, and is available in large, straight-grained pieces, lending this timber to a wide range of commercial uses.