Douglas-fir (Interior North)
Pseudotsuga menziesii
Douglas-fir (Interior North) measures 600 lbf on the Janka scale, about 47% as hard as northern red oak.
- Of the three Douglas-fir growth regions in the handbook, none is softer, and none bends more easily, shrinks less across the face or has a higher T/R ratio.
- Among the 37 U.S. softwoods, only longleaf pine is stronger in bending.
- Spanish-cedar has exactly the same Janka figure.
U.S. hardwoodsU.S. softwoodsImported woodsNorthern red oak
Six measures
Douglas-fir (Interior North)U.S. softwoods medianOther woods
Shrinkage across the face
6.9%radial 3.8%42nd lowest of 1553.5%12.7%Janka hardness
600 lbf2,669 N44th softest of 15510th of 37 U.S. softwoods240 lbf3,680 lbfDensity
0.450.48 at 12% MC53rd lightest of 1550.250.96Stiffness
1.79 M psi12.3 GPa59th stiffest of 1550.54 M psi4.06 M psiBending strength
13,100 psi90.3 MPa73rd strongest of 15528% above the U.S. softwoods median4,300 psi29,900 psiCupping tendency
1.8276th highest of 1551.092.90
How much it moves
Both its face shrinkage (6.9%) and its T/R ratio (1.82) sit in the middle half of the list.
0.41 in.
off a 6-inch flatsawn board, green to oven-dry; quartersawn 0.23 in.
- Tangential
- 6.9%
- Radial
- 3.8%
- Volume
- 10.7%
- T/R ratio
- 1.82 (79th most stable of 155)
End view, shrinkage drawn 3× life size.
Closest substitutes
- Tamarack
2% softer · 9% heavier · shrinks 0.5 points more across the face
- Red pine
7% softer · 9% lighter · shrinks 0.3 points more across the face
- Virginia pine
23% harder · same density · shrinks 0.3 points more across the face
Among the Douglas-fir growth regions
3rd hardest of 3, lbf.
Laboratory values
| Property | Green | Dry, 12% MC | Change when dried | Metric, 12% MC |
|---|---|---|---|---|
| Side hardness | 420lbf | 600lbf | +43% | 2,669N |
| Tension perpendicular | 340psi | 390psi | +15% | 2.70MPa |
| Impact bending | 22in. | 26in. | +18% | 660mm |
| Modulus of elasticity | 1.41M psi | 1.79M psi | +27% | 12.3GPa |
| Shear parallel to grain | 950psi | 1,400psi | +47% | 9.70MPa |
| Work to maximum load | 8.10in-lbf/in³ | 10.5in-lbf/in³ | +30% | 72.4kJ/m³ |
| Modulus of rupture | 7,400psi | 13,100psi | +77% | 90.3MPa |
| Compression parallel to grain | 3,470psi | 6,900psi | +99% | 47.6MPa |
| Compression perpendicular | 360psi | 770psi | +114% | 5.30MPa |
Wood Handbook Table 5-3b, Table 4-3. Data & method · Guides