Wood species
Loblolly pine wood
Loblolly pine is a softwood (Pinus taeda). At 12% moisture content it has a Janka hardness of 690 lbf (3,069 N) and it weighs about 36 lb/ft³ (571 kg/m³), 3 lb (1.35 kg) per board foot.
Also called: Pinus taeda.
Key numbers
- Janka hardness, 12% MC
- 690 lbf (3,069 N)
- Green: 450 lbf (2,002 N)
- Weight at 12% MC
- 36 lb/ft³ (571 kg/m³)
- 3 lb per board foot
- Specific gravity (oven-dry weight)
- 0.51 at 12% MC volume
- 0.47 on green volume
- Shrinkage, green to oven-dry
- 7.4% tangential
- Radial 4.8%, volumetric 12.3%
One source: USDA Forest Products Laboratory, the authority for species properties it measured
Why: Measured by the USDA Forest Products Laboratory; loblolly pine's density is worked from its specific gravity with the Handbook's own equation.
How much loblolly pine moves
A 12 in wide flatsawn board of loblolly pine that goes from 6% to 12% moisture content swells about 0.19 in (about 3/16 in, 4.7 mm). Quartersawn, the same board moves about 0.12 in (about 1/8 in, 3 mm). Flatsawn faces move 1.5 times as much as quartersawn ones, because the wood shrinks 7.4% around the growth rings but only 4.8% across them.
Worked with the Wood Handbook's dimensional change coefficients for loblolly pine (Table 13-5: 0.00259 tangential, 0.00165 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
- Yellowish white sapwood and reddish brown heartwood, like the other southern pines.
- Working and character
- Usually somewhat lighter than longleaf pine. All the southern pines have moderately high shrinkage but are dimensionally stable when properly dried.
- Uses
- Graded and sold as Southern Pine: framing, trusses, joists, plywood and preservative-treated lumber.
One of the four major Southern Pine species; it grows from Maryland south through the coastal plain into Florida and west into eastern Texas.
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 loblolly 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) | 7,300 psi (50 MPa) | 12,800 psi (88 MPa) |
| Stiffness (MOE) | 1,400,000 psi (9.7 GPa) | 1,790,000 psi (12.3 GPa) |
| Crushing strength (compression parallel to grain) | 3,510 psi (24 MPa) | 7,130 psi (49 MPa) |
| Compression perpendicular to grain | 390 psi (3 MPa) | 790 psi (5 MPa) |
| Shear parallel to grain | 860 psi (6 MPa) | 1,390 psi (10 MPa) |
| Tension perpendicular to grain | 260 psi (2 MPa) | 470 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
Buying and finishing loblolly pine
Work it out for your project
- Rank woods for your project with the species picker
Weigh loblolly pine against other woods on hardness, weight, movement and color, every figure from the Wood Handbook.
Why these numbers
Why these numbers?
The situation
The USDA Forest Products Laboratory measured loblolly pine at 690 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 × 0.51 × 1.12.
Arithmetic: exact by definition , sources [1]
The number
About 36 lb/ft³, or 3 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources