Wood species
American chestnut wood
American chestnut is a hardwood (Castanea dentata). At 12% moisture content it has a Janka hardness of 540 lbf (2,402 N) and it weighs about 30 lb/ft³ (482 kg/m³), 2.5 lb (1.14 kg) per board foot.
Also called: chestnut, sweet chestnut, wormy chestnut.
Key numbers
- Janka hardness, 12% MC
- 540 lbf (2,402 N)
- Green: 420 lbf (1,868 N)
- Weight at 12% MC
- 30 lb/ft³ (482 kg/m³)
- 2.5 lb per board foot
- Specific gravity (oven-dry weight)
- 0.43 at 12% MC volume
- 0.40 on green volume
- Shrinkage, green to oven-dry
- 6.7% tangential
- Radial 3.4%, volumetric 11.6%
One source: USDA Forest Products Laboratory, the authority for species properties it measured
Why: Measured by the USDA Forest Products Laboratory; American chestnut's density is worked from its specific gravity with the Handbook's own equation.
How much American chestnut moves
A 12 in wide flatsawn board of American chestnut that goes from 6% to 12% moisture content swells about 0.17 in (about 5/32 in, 4.3 mm). Quartersawn, the same board moves about 0.08 in (about 3/32 in, 2.1 mm). Flatsawn faces move 2 times as much as quartersawn ones, because the wood shrinks 6.7% around the growth rings but only 3.4% across them.
Worked with the Wood Handbook's dimensional change coefficients for American chestnut (Table 13-5: 0.00234 tangential, 0.00116 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
- Grayish brown to brown heartwood that darkens with age, and very narrow, almost white sapwood.
- Grain and texture
- Coarse, with growth rings marked by rows of large pores at the start of each year.
- Working and character
- Moderately light and moderately hard, low in stiffness; it dries well and is easy to work.
- Uses
- Today mostly as reclaimed “wormy chestnut” for paneling, interior woodwork and picture frames.
Blight killed practically every standing chestnut after the 1920s; the Handbook says supplies now come from salvaged timbers and the IUCN lists it as critically endangered.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-6.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Clear, straight-grained samples of American chestnut 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) | 5,600 psi (39 MPa) | 8,600 psi (59 MPa) |
| Stiffness (MOE) | 930,000 psi (6.4 GPa) | 1,230,000 psi (8.5 GPa) |
| Crushing strength (compression parallel to grain) | 2,470 psi (17 MPa) | 5,320 psi (37 MPa) |
| Compression perpendicular to grain | 310 psi (2 MPa) | 620 psi (4 MPa) |
| Shear parallel to grain | 800 psi (6 MPa) | 1,080 psi (7 MPa) |
| Tension perpendicular to grain | 440 psi (3 MPa) | 460 psi (3 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
Why these numbers
Why these numbers?
The situation
The USDA Forest Products Laboratory measured American chestnut at 540 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 × 0.43 × 1.12.
Arithmetic: exact by definition , sources [1]
The number
About 30 lb/ft³, or 2.5 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources