Wood species
Green ash wood
Green ash is a hardwood (Fraxinus pennsylvanica). At 12% moisture content it has a Janka hardness of 1,200 lbf (5,338 N) and it weighs about 39 lb/ft³ (627 kg/m³), 3.3 lb (1.48 kg) per board foot.
Also called: Fraxinus pennsylvanica.
Key numbers
- Janka hardness, 12% MC
- 1,200 lbf (5,338 N)
- Green: 870 lbf (3,870 N)
- Weight at 12% MC
- 39 lb/ft³ (627 kg/m³)
- 3.3 lb per board foot
- Specific gravity (oven-dry weight)
- 0.56 at 12% MC volume
- 0.53 on green volume
- Shrinkage, green to oven-dry
- 7.1% tangential
- Radial 4.6%, volumetric 12.5%
One source: USDA Forest Products Laboratory, the authority for species properties it measured
Why: Measured by the USDA Forest Products Laboratory; green ash's density is worked from its specific gravity with the Handbook's own equation.
How much green ash moves
A 12 in wide flatsawn board of green ash that goes from 6% to 12% moisture content swells about 0.18 in (about 3/16 in, 4.5 mm). Quartersawn, the same board moves about 0.11 in (about 1/8 in, 2.9 mm). Flatsawn faces move 1.5 times as much as quartersawn ones, because the wood shrinks 7.1% around the growth rings but only 4.6% across them.
Worked with the Wood Handbook's dimensional change coefficients for green ash (Table 13-5: 0.00248 tangential, 0.00158 radial per 1% change in moisture content), which hold between 6% and 14%. Individual boards vary: the Handbook gives shrinkage a coefficient of variation of about 15% (p. 4-11).
Color, grain and working
- Color
- Brown heartwood and light-colored to nearly white sapwood, like the rest of the white ash group.
- Working and character
- The Handbook describes the white ash group together: second-growth wood is heavy, strong, hard and stiff, with high shock resistance. Green ash from long-flooded southern river bottoms can grow buttresses of lightweight, brash wood.
- Uses
- Sold with the white ash group for decorative veneer, cabinets, furniture, flooring, millwork and crates.
The Handbook reports that the IUCN lists green ash as critically endangered because of the emerald ash borer.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-4.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Clear, straight-grained samples of green ash tested by the Forest Products Laboratory (Wood Handbook Table 5-3b). Knots and cross grain make lumber weaker than these clear samples (Handbook Chapter 5).
| Property | Green | 12% MC |
|---|---|---|
| Bending strength (MOR) | 9,500 psi (66 MPa) | 14,100 psi (97 MPa) |
| Stiffness (MOE) | 1,400,000 psi (9.7 GPa) | 1,660,000 psi (11.4 GPa) |
| Crushing strength (compression parallel to grain) | 4,200 psi (29 MPa) | 7,080 psi (49 MPa) |
| Compression perpendicular to grain | 730 psi (5 MPa) | 1,310 psi (9 MPa) |
| Shear parallel to grain | 1,260 psi (9 MPa) | 1,910 psi (13 MPa) |
| Tension perpendicular to grain | 590 psi (4 MPa) | 700 psi (5 MPa) |
A dash means the Handbook prints no value; none is filled in.
Dust and health
- Wood dust is classed as carcinogenic to humans (Group 1) by the International Agency for Research on Cancer, chiefly for cancers of the nose and sinuses.
- NIOSH recommends keeping wood dust exposure to 1 mg/m³ of total dust, as quoted in OSHA's sawmill guidance.
This is what the named authorities publish, not medical advice.
Compare with
Buying and finishing green ash
Work it out for your project
- Rank woods for furniture with the species picker
Weigh green ash against other woods on hardness, weight, movement and color, every figure from the Wood Handbook.
- Plan a finish for furniture in green ash
The finishes whose makers name that use, and a dated coat schedule from each product’s own sheet.
Why these numbers
Why these numbers?
The situation
The USDA Forest Products Laboratory measured green ash at 1,200 lbf of side hardness at 12% moisture content, on clear, straight-grained samples (Wood Handbook Table 5-3b).
One source: USDA Forest Products Laboratory, the authority for species properties it measured , sources [1]
What that means
Side hardness (Janka) is the load needed to press a 0.444 in (11.28 mm) steel ball halfway into the wood across the grain; a higher number dents less (Handbook p. 5-5).
One source: USDA Forest Products Laboratory, the authority for species properties it measured , sources [1]
So
Density at 12% is water's density × specific gravity × (1 + 0.12) (Handbook Eq. 4-14): 62.43 × 0.56 × 1.12.
Arithmetic: exact by definition , sources [1]
The number
About 39 lb/ft³, or 3.3 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources