Mountain hemlock
Tsuga mertensiana
Mountain hemlock measures 680 lbf on the Janka scale, 47% softer than northern red oak.
- Of the three hemlocks in the handbook, none is harder, and none has a T/R ratio closer to 1.
- Across all 155 woods it falls in the bottom fifth for stiffness.
- On the Janka scale its nearest neighbours are primavera at 660 lbf and loblolly pine at 690 lbf.
U.S. hardwoodsU.S. softwoodsImported woodsNorthern red oak
Six measures
Mountain hemlockU.S. softwoods medianOther woods
Stiffness
1.33 M psi9.2 GPa29th most flexible of 1550.54 M psi4.06 M psiDensity
0.420.45 at 12% MC45th lightest of 1550.250.96Cupping tendency
1.6145th lowest of 1551.092.90Shrinkage across the face
7.1%radial 4.4%48th lowest of 1553.5%12.7%Janka hardness
680 lbf3,025 N52nd softest of 1557th of 37 U.S. softwoods; 36% above the U.S. softwoods median240 lbf3,680 lbfBending strength
11,500 psi79.3 MPa58th weakest of 1554,300 psi29,900 psi
How much it moves
Both its face shrinkage (7.1%) and its T/R ratio (1.61) sit in the middle half of the list.
0.43 in.
off a 6-inch flatsawn board, green to oven-dry; quartersawn 0.26 in.
- Tangential
- 7.1%
- Radial
- 4.4%
- Volume
- 11.1%
- T/R ratio
- 1.61 (45th most stable of 155)
End view, shrinkage drawn 3× life size.
Closest substitutes
- Virginia pine
9% harder · 7% heavier · shrinks 0.1 points more across the face
- Jack pine
16% softer · 5% lighter · shrinks 0.5 points less across the face
- Black spruce
22% softer · 10% lighter · shrinks 0.3 points less across the face
Among the hemlocks
1st hardest of 3, lbf.
Laboratory values
| Property | Green | Dry, 12% MC | Change when dried | Metric, 12% MC |
|---|---|---|---|---|
| Modulus of elasticity | 1.04M psi | 1.33M psi | +28% | 9.17GPa |
| Side hardness | 470lbf | 680lbf | +45% | 3,025N |
| Modulus of rupture | 6,300psi | 11,500psi | +83% | 79.3MPa |
| Compression perpendicular | 370psi | 860psi | +132% | 5.90MPa |
| Impact bending | 32in. | 32in. | ±0% | 813mm |
| Work to maximum load | 11in-lbf/in³ | 10.4in-lbf/in³ | −5% | 71.7kJ/m³ |
| Compression parallel to grain | 2,880psi | 6,440psi | +124% | 44.4MPa |
| Shear parallel to grain | 930psi | 1,540psi | +66% | 10.6MPa |
| Tension perpendicular | 330psi | not tested | — | — |
Wood Handbook Table 5-3b, Table 4-3. Data & method · Guides