Sitka spruce (Picea sitchensis) in numbers: hardness, weight, strength, shrinkage, movement and decay resistance, taken from the tables of the USDA Forest Products Laboratory’s Wood Handbook, followed by what the wood is like to work and what it is used for. The values are averages from small, clear, straight-grained test specimens; real boards with knots, sloping grain or a different moisture content will differ.
| Property | Sitka spruce |
|---|---|
| Janka side hardness, 12% moisture | 510 lbf (2,269 N) |
| Janka side hardness, green | 350 lbf |
| Hardness rank | harder than 33 of the 168 woods with a 12% hardness value in our database |
| Density at 12% moisture | 28.0 lb/ft³ (448 kg/m³) |
| Weight per board foot (12%) | 2.33 lb |
| Specific gravity (ovendry weight, green volume) | 0.37 |
| Specific gravity at 12% moisture | 0.40 |
| Bending strength (modulus of rupture), 12% | 10,200 psi |
| Stiffness (modulus of elasticity), 12% | 1.57 million psi |
| Crushing strength (compression parallel to grain), 12% | 5,610 psi |
| Shrinkage green to ovendry: radial / tangential / volumetric | 4.3% / 7.5% / 11.5% |
| Tangential / radial shrinkage ratio | 1.74 |
| Dimensional change per 1% moisture (radial / tangential) | 0.00148 / 0.00263 |
| Impact bending (drop height to failure), 12% | 25 in. |
| Heartwood decay resistance | slightly or nonresistant |
The species in this group
Lumber is often sold under a group name. These are the species the Wood Handbook reports for this group, with the same properties side by side.
| Species | Janka (lbf) | Density (lb/ft³) | Bending (psi) | Stiffness (Mpsi) | Crushing (psi) | Shrink T/R (%) | Decay resistance |
|---|---|---|---|---|---|---|---|
| Sitka spruce Picea sitchensis | 510 | 28.0 | 10,200 | 1.57 | 5,610 | 7.5 / 4.3 | slightly or nonresistant |
| Engelmann spruce Picea engelmannii | 390 | 24.5 | 9,300 | 1.3 | 4,480 | 7.1 / 3.8 | slightly or nonresistant |
| White spruce Picea glauca | 410 | 25.2 | 9,400 | 1.43 | 5,180 | — | slightly or nonresistant |
| Red spruce Picea rubens | 530 | 28.0 | 10,800 | 1.66 | 5,540 | 7.8 / 3.8 | slightly or nonresistant |
| Black spruce Picea mariana | 530 | 29.4 | 10,800 | 1.61 | 5,960 | 6.8 / 4.1 | slightly or nonresistant |
What it is
Sitka spruce (Picea sitchensis) is a large tree of the northwestern coast of North America, from California to Alaska. Much Sitka spruce timber grows in Alaska, but most of those logs are sawn into cants for export to Pacific Rim countries; wood for US use comes mainly from Washington and Oregon. Engelmann spruce (P. engelmannii) grows at high elevations in the Rocky Mountains. The three eastern spruces are red (P. rubens), white (P. glauca) and black spruce (P. mariana): white and black spruce grow mainly in the Great Lake States and New England, and red spruce in New England and the Appalachian Mountains. The eastern species have about the same properties and are not distinguished from each other in commerce.
Sitka spruce heartwood is light pinkish brown, and the creamy white sapwood shades gradually into it; the sapwood may be 3 to 6 in. wide, or wider in young trees. Engelmann spruce heartwood is nearly white with a slight tinge of red. The eastern spruces are light in color with little difference between heartwood and sapwood.
Working properties
Sitka spruce has a comparatively fine, uniform texture, generally straight grain and no distinct taste or odor. It is moderately lightweight, moderately low in bending and compressive strength, moderately stiff, moderately soft and moderately low in shock resistance, with moderately low shrinkage. On the basis of its weight, though, it rates high in strength properties, and it can be obtained in long, clear, straight-grained pieces. The eastern spruces dry easily, are stable after drying and are easily worked. Engelmann spruce is the lightest and softest of the group and typically contains many small knots.
Weight and density
At 12% moisture content sitka spruce weighs about 28.0 lb per cubic foot, so one board foot (144 cubic inches) weighs about 2.33 lb. An 8 ft board of actual size 3/4 × 5-1/2 in. (a 1×6) holds 0.229 cubic feet and weighs about 6.4 lb; an 8 ft piece 1-1/2 × 3-1/2 in. (a 2×4 size) weighs about 8.2 lb. Green wood is much heavier because of the water it holds.
Density here is ovendry weight plus 12% water, divided by volume at 12% moisture content (Wood Handbook Eq. 4-12: density = specific gravity at 12% × 62.43 lb/ft³ × 1.12).
Wood movement
The Wood Handbook gives dimensional change coefficients for each species: the fraction of its width a board gains or loses for every 1% change in moisture content, between about 6% and 14%. For sitka spruce they are 0.00263 across a flatsawn face (tangential) and 0.00148 across a quartersawn face (radial).
Worked example: a flatsawn board 7-1/4 in. wide (a nominal 1×8) that goes from 6% moisture content in a heated winter house to 12% in a humid summer changes width by 7.25 × 0.00263 × 6 = 0.114 in. (about 1/8 in.). The same board quartersawn moves 0.064 in. (about 1/16 in.). Allow for this in panels, tabletops and floors; the wood movement calculator works it out for any size and moisture range.
How it compares
| Species | Janka (lbf) | Density (lb/ft³) | Bending (psi) | Stiffness (Mpsi) | Tangential shrink (%) | Decay resistance |
|---|---|---|---|---|---|---|
| Sitka spruce | 510 | 28.0 | 10,200 | 1.57 | 7.5 | slightly or nonresistant |
| Western hemlock | 540 | 31.5 | 11,300 | 1.63 | 7.8 | slightly or nonresistant |
| White fir | 480 | 27.3 | 9,800 | 1.5 | 7.0 | slightly or nonresistant |
| Douglas-fir (Coast) | 710 | 33.6 | 12,400 | 1.95 | 7.6 | moderately resistant |
| Eastern white pine | 380 | 24.5 | 8,600 | 1.24 | 6.1 | moderately resistant (old growth only); otherwise slightly or nonresistant |
| Western redcedar | 350 | 22.4 | 7,500 | 1.11 | 5.0 | resistant |
Uses
Sitka spruce: lumber, pulpwood and cooperage, boxes and crates, furniture, planing-mill products, sashes, doors, blinds, millwork and boats. It has been by far the most important wood for aircraft construction, and its specialty uses include ladder rails and piano sounding boards. Eastern spruce goes mostly to pulpwood, with lumber for framing, general millwork, boxes and crates and piano sounding boards. Engelmann spruce is used for lumber, mine timbers, railroad crossties and poles, for dimension lumber, flooring and sheathing, and for pulp and papermaking.
Frequently asked questions
How hard is spruce?
Sitka spruce averages 510 lbf (2,269 N) on the Janka test at 12% moisture content. The five spruces in the Wood Handbook range from 390 lbf (Engelmann spruce) to 530 lbf (red and black spruce).
Why is Sitka spruce used for aircraft?
For its weight it rates high in strength, and it can be obtained in long, clear, straight-grained pieces. The Handbook calls it by far the most important wood for aircraft construction.
How much does spruce weigh?
Sitka spruce weighs about 28.0 lb per cubic foot at 12% moisture content, or 2.33 lb per board foot. Engelmann spruce is the lightest of the five spruces in the table.
Can spruce be used outdoors?
Not untreated. Spruce heartwood is in the slightly or nonresistant decay class, which usually needs some form of preservative treatment where there is a decay hazard.
Sources
- USDA Forest Products Laboratory. Wood Handbook: Wood as an Engineering Material. General Technical Report FPL-GTR-190, 2010. Chapter 2 (species descriptions), Chapter 4 (Tables 4-3, 4-4 shrinkage; Eq. 4-7, 4-9, 4-12 density), Chapter 5 (Tables 5-3b, 5-5b strength and hardness), Chapter 13 (Table 13-5 dimensional change coefficients), Chapter 14 (Table 14-1 decay resistance)
- USDA Forest Products Laboratory. Wood Handbook, 2021 edition (FPL-GTR-282)
Last reviewed: 24 October 2026. Numbers are generated from our parsed copy of the Handbook tables, so every page uses the same data. Values marked * are estimates computed with the Handbook’s own equations. Spotted an error? Please let us know.