Western hemlock (Tsuga heterophylla) 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 | Western hemlock |
|---|---|
| Janka side hardness, 12% moisture | 540 lbf (2,402 N) |
| Janka side hardness, green | 410 lbf |
| Hardness rank | harder than 39 of the 168 woods with a 12% hardness value in our database |
| Density at 12% moisture | 31.5 lb/ft³ (504 kg/m³) |
| Weight per board foot (12%) | 2.62 lb |
| Specific gravity (ovendry weight, green volume) | 0.42 |
| Specific gravity at 12% moisture | 0.45 |
| Bending strength (modulus of rupture), 12% | 11,300 psi |
| Stiffness (modulus of elasticity), 12% | 1.63 million psi |
| Crushing strength (compression parallel to grain), 12% | 7,200 psi |
| Shrinkage green to ovendry: radial / tangential / volumetric | 4.2% / 7.8% / 12.4% |
| Tangential / radial shrinkage ratio | 1.86 |
| Dimensional change per 1% moisture (radial / tangential) | 0.00144 / 0.00274 |
| Impact bending (drop height to failure), 12% | 23 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 |
|---|---|---|---|---|---|---|---|
| Western hemlock Tsuga heterophylla | 540 | 31.5 | 11,300 | 1.63 | 7,200 | 7.8 / 4.2 | slightly or nonresistant |
| Eastern hemlock Tsuga canadensis | 500 | 28.0 | 8,900 | 1.2 | 5,410 | 6.8 / 3.0 | slightly or nonresistant |
| Mountain hemlock Tsuga mertensiana | 680 | 31.5 | 11,500 | 1.33 | 6,440 | 7.1 / 4.4 | slightly or nonresistant |
What it is
Western hemlock (Tsuga heterophylla), also sold as West Coast hemlock, Pacific hemlock and western hemlock-fir, grows along the Pacific coast of Oregon and Washington and in the northern Rocky Mountains, north to Canada and Alaska. Its relative mountain hemlock (T. mertensiana) grows in mountainous country from central California to Alaska and is treated as a separate species when lumber properties are assigned. Eastern hemlock (T. canadensis) grows from New England to northern Alabama and Georgia and in the Great Lake States, and its production is divided fairly evenly among the New England, Middle Atlantic and Great Lake States.
The heartwood and sapwood of western hemlock are almost white with a purplish tinge, and the sapwood is generally not more than 1 in. wide. The wood often contains small, sound, black knots that are usually tight and dimensionally stable. Dark streaks in the lumber are caused by hemlock bark maggots and generally do not reduce strength. Eastern hemlock heartwood is pale brown with a reddish hue; its wood is coarse and uneven in texture, and old trees tend to have considerable shake.
Working properties
Western hemlock is moderately light in weight and moderate in strength, hardness, stiffness and shock resistance. Its shrinkage is moderately high, about the same as Douglas-fir (7.8% tangentially from green to ovendry). Green hemlock lumber holds considerably more water than Douglas-fir and needs a longer kiln-drying time. Mountain hemlock has about the same density as western hemlock but is less stiff. Eastern hemlock is moderately lightweight, moderately hard, moderately low in strength, moderately stiff and moderately low in shock resistance.
Weight and density
At 12% moisture content western hemlock weighs about 31.5 lb per cubic foot, so one board foot (144 cubic inches) weighs about 2.62 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 7.2 lb; an 8 ft piece 1-1/2 × 3-1/2 in. (a 2×4 size) weighs about 9.2 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 western hemlock they are 0.00274 across a flatsawn face (tangential) and 0.00144 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 × 0.00274 × 6 = 0.119 in. (about 1/8 in.). The same board quartersawn moves 0.063 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 |
|---|---|---|---|---|---|---|
| Western hemlock | 540 | 31.5 | 11,300 | 1.63 | 7.8 | slightly or nonresistant |
| Douglas-fir (Coast) | 710 | 33.6 | 12,400 | 1.95 | 7.6 | moderately resistant |
| Sitka spruce | 510 | 28.0 | 10,200 | 1.57 | 7.5 | slightly or nonresistant |
| White fir | 480 | 27.3 | 9,800 | 1.5 | 7.0 | slightly or nonresistant |
| Loblolly pine | 690 | 35.7 | 12,800 | 1.79 | 7.4 | slightly or nonresistant |
| Eastern white pine | 380 | 24.5 | 8,600 | 1.24 | 6.1 | moderately resistant (old growth only); otherwise slightly or nonresistant |
Uses
Western and mountain hemlock are used principally for pulpwood, lumber and plywood; the lumber goes mainly into building material and into boxes, pallets, crates, flooring, furniture and ladders. Eastern hemlock is used mostly for lumber and pulpwood, the lumber mainly in building construction and for boxes, pallets and crates.
Frequently asked questions
How hard is hemlock?
Western hemlock averages 540 lbf (2,402 N) on the Janka test at 12% moisture content. Of the three hemlocks, eastern hemlock is softest at 500 lbf and mountain hemlock hardest at 680 lbf.
Is hemlock as strong as Douglas-fir?
Not quite. Clear western hemlock averages 11,300 psi in bending against 12,400 psi for coast Douglas-fir, and it is softer (540 against 710 lbf). These are small clear-specimen values; graded lumber has its own design values in the building code.
Why does hemlock take longer to dry?
Green hemlock lumber contains considerably more water than Douglas-fir, and the Handbook notes that it requires a longer kiln-drying time.
Can hemlock be used outdoors?
Not untreated. Hemlock 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.