Sitka spruce

Picea sitchensis (Bong.) Carr. · Softwood · North America

Janka 510 lbf≈25 lb/ft³ dried (est.)

Properties

Janka hardness	510 lbf (2,268 N)
Average dried weight (est.)	25 lb/ft³ (400 kg/m³)
Specific gravity	0.40
Modulus of rupture	10,200 psi (70.3 MPa)
Modulus of elasticity	1.57 million psi (10.83 GPa)
Crushing strength	5,610 psi (38.7 MPa)
Shrinkage — radial	4.3%
Shrinkage — tangential	7.5%
Shrinkage — volumetric	11.5%
Shrinkage T/R ratio	1.7

Values at 12% moisture content, clear-wood averages. Source: USDA Forest Products Laboratory, Wood Handbook FPL-GTR-282 (2021), Table 5-3 p. 5-13; shrinkage Table 4-3 p. 4-8.

Sitka spruce is a moderately lightweight softwood (specific gravity 0.40, Janka hardness 510 lbf) with an unusually high strength for its weight. It is available in long, clear, straight-grained pieces, which made it the most important wood for aircraft construction and keeps it in demand for ladders and piano sounding boards.

Appearance & grain

The heartwood is light pinkish brown. The sapwood is creamy white, shades gradually into the heartwood, and runs 3 to 6 inches wide, wider in young trees. The texture is comparatively fine and uniform, the grain generally straight, and the wood has no distinct taste or odor.

Workability

The Handbook highlights the combination that defines the species: moderate weight with high strength, in long clear lengths of straight-grained stock. It gives no separate machining caveat for Sitka spruce.