Wood species
Sugar pine wood
Sugar pine is a softwood (Pinus lambertiana). At 12% moisture content it has a Janka hardness of 380 lbf (1,690 N) and it weighs about 25 lb/ft³ (403 kg/m³), 2.1 lb (0.95 kg) per board foot.
Also called: California sugar pine.
Key numbers
- Janka hardness, 12% MC
- 380 lbf (1,690 N)
- Green: 270 lbf (1,201 N)
- Weight at 12% MC
- 25 lb/ft³ (403 kg/m³)
- 2.1 lb per board foot
- Specific gravity (oven-dry weight)
- 0.36 at 12% MC volume
- 0.34 on green volume
- Shrinkage, green to oven-dry
- 5.6% tangential
- Radial 2.9%, volumetric 7.9%
One source: USDA Forest Products Laboratory, the authority for species properties it measured
Why: Measured by the USDA Forest Products Laboratory; sugar pine's density is worked from its specific gravity with the Handbook's own equation.
How much sugar pine moves
A 12 in wide flatsawn board of sugar pine that goes from 6% to 12% moisture content swells about 0.14 in (about 1/8 in, 3.5 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 5.6% around the growth rings but only 2.9% across them.
Worked with the Wood Handbook's dimensional change coefficients for sugar pine (Table 13-5: 0.00194 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
- Buff or light brown heartwood, sometimes tinged red; creamy white sapwood.
- Grain and texture
- Straight and fairly uniform.
- Working and character
- Light, soft and fairly weak, with very low shrinkage. It dries without warping or checking, stays stable, cuts easily and nails well.
- Uses
- Foundry patterns, sashes, doors, frames, millwork and building construction.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-16.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Clear, straight-grained samples of sugar pine 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) | 4,900 psi (34 MPa) | 8,200 psi (57 MPa) |
| Stiffness (MOE) | 1,030,000 psi (7.1 GPa) | 1,190,000 psi (8.2 GPa) |
| Crushing strength (compression parallel to grain) | 2,460 psi (17 MPa) | 4,460 psi (31 MPa) |
| Compression perpendicular to grain | 210 psi (1 MPa) | 500 psi (3 MPa) |
| Shear parallel to grain | 720 psi (5 MPa) | 1,130 psi (8 MPa) |
| Tension perpendicular to grain | 270 psi (2 MPa) | 350 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 sugar pine at 380 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 × 0.36 × 1.12.
Arithmetic: exact by definition , sources [1]
The number
About 25 lb/ft³, or 2.1 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources