Black ash
Fraxinus nigra
Black ash measures 850 lbf on the Janka scale, 34% softer than northern red oak.
- Of the four ashes in the handbook, none is softer or lighter.
- Drying hardens it more than most: from 520 lbf green, it gains 63% by 12% moisture, where the median wood gains 31%.
- Bigleaf maple and sweetgum have exactly the same Janka figure.
U.S. hardwoodsU.S. softwoodsImported woodsNorthern red oak
Six measures
Black ashU.S. hardwoods medianOther woods
Cupping tendency
1.5631st lowest of 1551.092.90Density
0.450.49 at 12% MC53rd lightest of 1550.250.96Janka hardness
850 lbf3,781 N68th softest of 15538th of 53 U.S. hardwoods; 27% below the U.S. hardwoods median240 lbf3,680 lbfStiffness
1.60 M psi11.0 GPa69th most flexible of 1550.54 M psi4.06 M psiBending strength
12,600 psi86.9 MPa70th weakest of 1554,300 psi29,900 psiShrinkage across the face
7.8%radial 5.0%76th highest of 1553.5%12.7%
How much it moves
The two directions move almost alike (T/R 1.56), so flatsawn and quartersawn boards differ by only 0.17 in.
0.47 in.
off a 6-inch flatsawn board, green to oven-dry
- Tangential
- 7.8%
- Radial
- 5.0%
- Volume
- 15.2%
- T/R ratio
- 1.56 (31st most stable of 155)
End view, shrinkage drawn 3× life size.
Closest substitutes
- Slippery elm
1% harder · 7% heavier · shrinks 1.1 points more across the face
- American sycamore
9% softer · 2% heavier · shrinks 0.6 points more across the face
- Cucumbertree
18% softer · 2% lighter · shrinks 1.0 points more across the face
Among the ashes
4th hardest of 4, lbf.
Laboratory values
| Property | Green | Dry, 12% MC | Change when dried | Metric, 12% MC |
|---|---|---|---|---|
| Tension perpendicular | 490psi | 700psi | +43% | 4.80MPa |
| Work to maximum load | 12.1in-lbf/in³ | 14.9in-lbf/in³ | +23% | 102.7kJ/m³ |
| Impact bending | 33in. | 35in. | +6% | 889mm |
| Compression parallel to grain | 2,300psi | 5,970psi | +160% | 41.2MPa |
| Side hardness | 520lbf | 850lbf | +63% | 3,781N |
| Modulus of elasticity | 1.04M psi | 1.60M psi | +54% | 11.0GPa |
| Modulus of rupture | 6,000psi | 12,600psi | +110% | 86.9MPa |
| Compression perpendicular | 350psi | 760psi | +117% | 5.20MPa |
| Shear parallel to grain | 860psi | 1,570psi | +83% | 10.8MPa |
Wood Handbook Table 5-3b, Table 4-3. Data & method · Guides