Red alder
Alnus rubra
Red alder measures 590 lbf on the Janka scale, about 46% as hard as northern red oak.
- Tamarack has exactly the same Janka figure.
- Across all 155 woods it falls in the bottom fifth for density.
- On the Janka scale its nearest neighbours are yellow-cedar at 580 lbf and Douglas-fir (Interior North) at 600 lbf.
U.S. hardwoodsU.S. softwoodsImported woodsNorthern red oak
Six measures
Red alderU.S. hardwoods medianOther woods
Density
0.370.41 at 12% MC23rd lightest of 15529% below the U.S. hardwoods median0.250.96Bending strength
9,800 psi67.6 MPa34th weakest of 1554,300 psi29,900 psiStiffness
1.38 M psi9.5 GPa36th most flexible of 1550.54 M psi4.06 M psiJanka hardness
590 lbf2,624 N42nd softest of 15546th of 53 U.S. hardwoods; 49% below the U.S. hardwoods median240 lbf3,680 lbfCupping tendency
1.6651st lowest of 1551.092.90Shrinkage across the face
7.3%radial 4.4%58th lowest of 1553.5%12.7%
How much it moves
Both its face shrinkage (7.3%) and its T/R ratio (1.66) sit in the middle half of the list.
0.44 in.
off a 6-inch flatsawn board, green to oven-dry; quartersawn 0.26 in.
- Tangential
- 7.3%
- Radial
- 4.4%
- Volume
- 12.6%
- T/R ratio
- 1.66 (51st most stable of 155)
End view, shrinkage drawn 3× life size.
Closest substitutes
- Yellow-poplar
8% softer · 8% heavier · shrinks 0.9 points more across the face
- Spanish-cedar
2% harder · 11% heavier · shrinks 1.0 points less across the face
- Ilomba
3% harder · 8% heavier · shrinks 1.1 points more across the face
Woods of similar hardness
The eight nearest on the Janka scale, lbf.
Laboratory values
| Property | Green | Dry, 12% MC | Change when dried | Metric, 12% MC |
|---|---|---|---|---|
| Compression perpendicular | 250psi | 440psi | +76% | 3.00MPa |
| Impact bending | 22in. | 20in. | −9% | 508mm |
| Shear parallel to grain | 770psi | 1,080psi | +40% | 7.40MPa |
| Modulus of rupture | 6,500psi | 9,800psi | +51% | 67.6MPa |
| Modulus of elasticity | 1.17M psi | 1.38M psi | +18% | 9.51GPa |
| Work to maximum load | 8.00in-lbf/in³ | 8.40in-lbf/in³ | +5% | 57.9kJ/m³ |
| Side hardness | 440lbf | 590lbf | +34% | 2,624N |
| Compression parallel to grain | 2,960psi | 5,820psi | +97% | 40.1MPa |
| Tension perpendicular | 390psi | 420psi | +8% | 2.90MPa |
Wood Handbook Table 5-3b, Table 4-3. Data & method · Guides