Jarrah
Eucalyptus marginata
Jarrah measures 1,910 lbf on the Janka scale, 48% harder than northern red oak.
- Only greenheart, azobe and karri shrink more through the thickness, and only five woods lose more volume on drying.
- It sits in the top quarter of the list for both hardness and shrinkage across the face.
- Its volumetric shrinkage is 50% above the median for imported woods.
U.S. hardwoodsU.S. softwoodsImported woodsNorthern red oak
Six measures
JarrahImported woods medianOther woods
Shrinkage across the face
11.0%radial 7.7%11th highest of 15539% above the imported woods median3.5%12.7%Cupping tendency
1.4317th lowest of 1551.092.90Janka hardness
1,910 lbf8,496 N21st hardest of 15519th of 65 imported woods; 47% above the imported woods median240 lbf3,680 lbfDensity
0.6722nd heaviest of 1550.250.96Bending strength
16,200 psi111.7 MPa43rd strongest of 1554,300 psi29,900 psiStiffness
1.88 M psi13.0 GPa49th stiffest of 1550.54 M psi4.06 M psi
How much it moves
It shrinks a lot, but the two directions stay close (T/R 1.43), so a board loses size more than it changes shape.
0.66 in.
off a 6-inch flatsawn board, green to oven-dry; quartersawn 0.46 in.
- Tangential
- 11.0%
- Radial
- 7.7%
- Volume
- 18.7%
- T/R ratio
- 1.43 (17th most stable of 155)
End view, shrinkage drawn 3× life size.
Closest substitutes
- Mockernut hickory
3% harder · 4% lighter · same face shrinkage
- Shellbark hickory
5% softer · 8% lighter · shrinks 1.6 points more across the face
- Shagbark hickory
2% softer · 4% lighter · shrinks 0.5 points less 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 |
|---|---|---|---|---|
| Shear parallel to grain | 1,320psi | 2,130psi | +61% | 14.7MPa |
| Side hardness | 1,290lbf | 1,910lbf | +48% | 8,496N |
| Compression parallel to grain | 5,190psi | 8,870psi | +71% | 61.2MPa |
| Modulus of rupture | 9,900psi | 16,200psi | +64% | 111.7MPa |
| Modulus of elasticity | 1.48M psi | 1.88M psi | +27% | 13.0GPa |
Wood Handbook Table 5-5b, Table 4-4. Data & method · Guides