Wood species
Balsam fir wood
Balsam fir is a softwood (Abies balsamea). At 12% moisture content it has a Janka hardness of 380 lbf (1,690 N) and it weighs about 24 lb/ft³ (392 kg/m³), 2 lb (0.93 kg) per board foot.
Also called: Abies balsamea.
Key numbers
- Janka hardness, 12% MC
- 380 lbf (1,690 N)
- Green: 290 lbf (1,290 N)
- Weight at 12% MC
- 24 lb/ft³ (392 kg/m³)
- 2 lb per board foot
- Specific gravity (oven-dry weight)
- 0.35 at 12% MC volume
- 0.33 on green volume
- Shrinkage, green to oven-dry
- 6.9% tangential
- Radial 2.9%, volumetric 11.2%
One source: USDA Forest Products Laboratory, the authority for species properties it measured
Why: Measured by the USDA Forest Products Laboratory; balsam fir's density is worked from its specific gravity with the Handbook's own equation.
How much balsam fir moves
A 12 in wide flatsawn board of balsam fir that goes from 6% to 12% moisture content swells about 0.17 in (about 3/16 in, 4.4 mm). Quartersawn, the same board moves about 0.07 in (about 1/16 in, 1.8 mm). Flatsawn faces move 2.4 times as much as quartersawn ones, because the wood shrinks 6.9% around the growth rings but only 2.9% across them.
Worked with the Wood Handbook's dimensional change coefficients for balsam fir (Table 13-5: 0.00241 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
- Creamy white to pale brown; heartwood and sapwood look alike.
- Working and character
- Lightweight and soft, with low bending and compressive strength, moderately low stiffness and low shock resistance.
- Uses
- Mostly pulpwood, with some structural lumber, especially in New England and the Great Lakes States.
The Handbook says the true firs cannot be told apart by their wood alone, and that the balsam woolly adelgid, an insect introduced from Europe, attacks all of them.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-12.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Clear, straight-grained samples of balsam fir 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) | 5,500 psi (38 MPa) | 9,200 psi (63 MPa) |
| Stiffness (MOE) | 1,250,000 psi (8.6 GPa) | 1,450,000 psi (10 GPa) |
| Crushing strength (compression parallel to grain) | 2,630 psi (18 MPa) | 5,280 psi (36 MPa) |
| Compression perpendicular to grain | 190 psi (1 MPa) | 400 psi (3 MPa) |
| Shear parallel to grain | 660 psi (5 MPa) | 940 psi (6 MPa) |
| Tension perpendicular to grain | 180 psi (1 MPa) | 180 psi (1 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 balsam fir
Work it out for your project
- Rank woods for your project with the species picker
Weigh balsam fir 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 balsam fir 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 × 0.35 × 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