Wood species
Atlantic white cedar wood
Atlantic white cedar is a softwood (Chamaecyparis thyoides). At 12% moisture content it has a Janka hardness of 350 lbf (1,557 N) and it weighs about 22 lb/ft³ (358 kg/m³), 1.9 lb (0.85 kg) per board foot.
Also called: Atlantic white-cedar, southern white-cedar, swamp-cedar, boat-cedar.
Key numbers
- Janka hardness, 12% MC
- 350 lbf (1,557 N)
- Green: 290 lbf (1,290 N)
- Weight at 12% MC
- 22 lb/ft³ (358 kg/m³)
- 1.9 lb per board foot
- Specific gravity (oven-dry weight)
- 0.32 at 12% MC volume
- 0.31 on green volume
- Shrinkage, green to oven-dry
- 5.4% tangential
- Radial 2.9%, volumetric 8.8%
One source: USDA Forest Products Laboratory, the authority for species properties it measured
Why: Measured by the USDA Forest Products Laboratory; Atlantic white cedar's density is worked from its specific gravity with the Handbook's own equation.
How much Atlantic white cedar moves
A 12 in wide flatsawn board of Atlantic white-cedar that goes from 6% to 12% moisture content swells about 0.13 in (about 1/8 in, 3.4 mm). Quartersawn, the same board moves about 0.07 in (about 1/16 in, 1.8 mm). Flatsawn faces move 1.9 times as much as quartersawn ones, because the wood shrinks 5.4% around the growth rings but only 2.9% across them.
Worked with the Wood Handbook's dimensional change coefficients for Atlantic white-cedar (Table 13-5: 0.00187 tangential, 0.00099 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
- Light brown heartwood and narrow white sapwood.
- Working and character
- Light, rather soft, low in strength and shock resistance, with little shrinkage. Easy to work, holds paint well, and the heartwood resists decay strongly.
- Uses
- Boats, shingles, posts, poles, cabin logs, decorative fencing and water tanks.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-18.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Clear, straight-grained samples of Atlantic white-cedar 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) | 4,700 psi (32 MPa) | 6,800 psi (47 MPa) |
| Stiffness (MOE) | 750,000 psi (5.2 GPa) | 930,000 psi (6.4 GPa) |
| Crushing strength (compression parallel to grain) | 2,390 psi (16 MPa) | 4,700 psi (32 MPa) |
| Compression perpendicular to grain | 240 psi (2 MPa) | 410 psi (3 MPa) |
| Shear parallel to grain | 690 psi (5 MPa) | 800 psi (6 MPa) |
| Tension perpendicular to grain | 180 psi (1 MPa) | 220 psi (2 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 Atlantic white-cedar at 350 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 × 0.32 × 1.12.
Arithmetic: exact by definition , sources [1]
The number
About 22 lb/ft³, or 1.9 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources