Wood species
Alaska yellow cedar wood
Alaska yellow cedar is a softwood (Chamaecyparis nootkatensis). At 12% moisture content it has a Janka hardness of 580 lbf (2,580 N) and it weighs about 31 lb/ft³ (493 kg/m³), 2.6 lb (1.16 kg) per board foot.
Also called: yellow-cedar, yellow cedar.
Key numbers
- Janka hardness, 12% MC
- 580 lbf (2,580 N)
- Green: 440 lbf (1,957 N)
- Weight at 12% MC
- 31 lb/ft³ (493 kg/m³)
- 2.6 lb per board foot
- Specific gravity (oven-dry weight)
- 0.44 at 12% MC volume
- 0.42 on green volume
- Shrinkage, green to oven-dry
- 6.0% tangential
- Radial 2.8%, volumetric 9.2%
One source: USDA Forest Products Laboratory, the authority for species properties it measured
Why: Measured by the USDA Forest Products Laboratory; Alaska yellow cedar's density is worked from its specific gravity with the Handbook's own equation.
How much Alaska yellow cedar moves
A 12 in wide flatsawn board of yellow-cedar that goes from 6% to 12% moisture content swells about 0.15 in (about 5/32 in, 3.8 mm). Quartersawn, the same board moves about 0.07 in (about 1/16 in, 1.7 mm). Flatsawn faces move 2.1 times as much as quartersawn ones, because the wood shrinks 6.0% around the growth rings but only 2.8% across them.
Worked with the Wood Handbook's dimensional change coefficients for yellow-cedar (Table 13-5: 0.00208 tangential, 0.00095 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
- Bright, clear yellow heartwood; narrow white to yellowish sapwood that is hard to tell apart.
- Grain and texture
- Fine texture and generally straight grain, with a mild, distinctive smell.
- Working and character
- Moderately heavy, strong, stiff and hard. It shrinks little, is stable once dry, and the heartwood is very decay resistant.
- Uses
- Interior woodwork, furniture, small boats, cabinetwork and novelties.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-19.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Clear, straight-grained samples of yellow-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) | 6,400 psi (44 MPa) | 11,100 psi (77 MPa) |
| Stiffness (MOE) | 1,140,000 psi (7.9 GPa) | 1,420,000 psi (9.8 GPa) |
| Crushing strength (compression parallel to grain) | 3,050 psi (21 MPa) | 6,310 psi (44 MPa) |
| Compression perpendicular to grain | 350 psi (2 MPa) | 620 psi (4 MPa) |
| Shear parallel to grain | 840 psi (6 MPa) | 1,130 psi (8 MPa) |
| Tension perpendicular to grain | 330 psi (2 MPa) | 360 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 yellow-cedar at 580 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 × 0.44 × 1.12.
Arithmetic: exact by definition , sources [1]
The number
About 31 lb/ft³, or 2.6 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources