Wood species
Red pine wood
Red pine is a softwood (Pinus resinosa). At 12% moisture content it has a Janka hardness of 560 lbf (2,491 N) and it weighs about 32 lb/ft³ (515 kg/m³), 2.7 lb (1.22 kg) per board foot.
Also called: Norway pine.
Key numbers
- Janka hardness, 12% MC
- 560 lbf (2,491 N)
- Green: 340 lbf (1,512 N)
- Weight at 12% MC
- 32 lb/ft³ (515 kg/m³)
- 2.7 lb per board foot
- Specific gravity (oven-dry weight)
- 0.46 at 12% MC volume
- 0.41 on green volume
- Shrinkage, green to oven-dry
- 7.2% tangential
- Radial 3.8%, volumetric 11.3%
One source: USDA Forest Products Laboratory, the authority for species properties it measured
Why: Measured by the USDA Forest Products Laboratory; red pine's density is worked from its specific gravity with the Handbook's own equation.
How much red pine moves
A 12 in wide flatsawn board of red pine that goes from 6% to 12% moisture content swells about 0.18 in (about 3/16 in, 4.6 mm). Quartersawn, the same board moves about 0.09 in (about 3/32 in, 2.4 mm). Flatsawn faces move 1.9 times as much as quartersawn ones, because the wood shrinks 7.2% around the growth rings but only 3.8% across them.
Worked with the Wood Handbook's dimensional change coefficients for red pine (Table 13-5: 0.00252 tangential, 0.0013 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
- Pale red to reddish-brown heartwood; nearly white sapwood with a yellowish tinge, 2 to 4 in. wide.
- Grain and texture
- Generally straight, less even than eastern white pine, and somewhat resinous.
- Working and character
- Moderately heavy, strong and stiff, moderately soft. It shrinks a fair amount but dries easily and is stable once dry.
- Uses
- Building lumber, treated decking, siding, flooring, cabin logs and millwork.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-15.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Clear, straight-grained samples of red 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) | 5,800 psi (40 MPa) | 11,000 psi (76 MPa) |
| Stiffness (MOE) | 1,280,000 psi (8.8 GPa) | 1,630,000 psi (11.2 GPa) |
| Crushing strength (compression parallel to grain) | 2,730 psi (19 MPa) | 6,070 psi (42 MPa) |
| Compression perpendicular to grain | 260 psi (2 MPa) | 600 psi (4 MPa) |
| Shear parallel to grain | 690 psi (5 MPa) | 1,210 psi (8 MPa) |
| Tension perpendicular to grain | 300 psi (2 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 red pine at 560 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 × 0.46 × 1.12.
Arithmetic: exact by definition , sources [1]
The number
About 32 lb/ft³, or 2.7 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources