Wood species
Balsam poplar wood
Balsam poplar is a hardwood (Populus balsamifera). It weighs about 24 lb/ft³ (381 kg/m³), 2 lb (0.9 kg) per board foot.
Also called: Populus balsamifera.
Key numbers
- Janka hardness, 12% MC
- Not measured
- Weight at 12% MC
- 24 lb/ft³ (381 kg/m³)
- 2 lb per board foot
- Specific gravity (oven-dry weight)
- 0.34 at 12% MC volume
- 0.31 on green volume
- Shrinkage, green to oven-dry
- 7.1% tangential
- Radial 3.0%, volumetric 10.5%
One source: USDA Forest Products Laboratory, the authority for species properties it measured
Why: Measured by the USDA Forest Products Laboratory; balsam poplar's density is worked from its specific gravity with the Handbook's own equation.
How much balsam poplar moves
A 12 in wide flatsawn board of balsam poplar that goes from 6% to 12% moisture content swells about 0.18 in (about 3/16 in, 4.5 mm). Quartersawn, the same board moves about 0.07 in (about 1/16 in, 1.9 mm). Flatsawn faces move 2.4 times as much as quartersawn ones, because the wood shrinks 7.1% around the growth rings but only 3.0% across them.
Worked with the Wood Handbook's dimensional change coefficients for balsam poplar (Table 13-5: 0.00248 tangential, 0.00102 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
- Grayish white to light brown heartwood, as the Handbook describes the cottonwoods.
- Grain and texture
- Fairly uniform texture, generally straight grained.
- Working and character
- The Handbook groups balsam poplar with the cottonwoods and describes them together; its own figures are in the table.
- Uses
- With the cottonwoods: lumber, veneer and pulpwood for boxes, crates, baskets and pallets.
It grows from Alaska across Canada and in the northern Great Lakes States.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-6.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Clear, straight-grained samples of balsam poplar 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) | 3,900 psi (27 MPa) | 6,800 psi (47 MPa) |
| Stiffness (MOE) | 750,000 psi (5.2 GPa) | 1,100,000 psi (7.6 GPa) |
| Crushing strength (compression parallel to grain) | 1,690 psi (12 MPa) | 4,020 psi (28 MPa) |
| Compression perpendicular to grain | 140 psi (1 MPa) | 300 psi (2 MPa) |
| Shear parallel to grain | 500 psi (3 MPa) | 790 psi (5 MPa) |
| Tension perpendicular to grain | — | — |
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 balsam poplar
Work it out for your project
- Rank woods for your project with the species picker
Weigh balsam poplar against other woods on hardness, weight, movement and color, every figure from the Wood Handbook.
Why these numbers
Why these numbers?
The situation
The Wood Handbook prints no side hardness for balsam poplar (Table 5-3b shows "—"), so none is given here.
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 × 0.34 × 1.12.
Arithmetic: exact by definition , sources [1]
The number
About 24 lb/ft³, or 2 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources