Wood species
Parana pine wood
Parana pine is a softwood (Araucaria angustifolia). At 12% moisture content it has a Janka hardness of 780 lbf (3,470 N) and it weighs about 35 lb/ft³ (554 kg/m³), 2.9 lb (1.31 kg) per board foot.
Also called: parana-pine.
Key numbers
- Janka hardness, 12% MC
- 780 lbf (3,470 N)
- Green: 560 lbf (2,491 N)
- Weight at 12% MC
- 35 lb/ft³ (554 kg/m³)
- 2.9 lb per board foot
- Specific gravity (oven-dry weight)
- 0.46 on green volume
- Shrinkage, green to oven-dry
- 7.9% tangential
- Radial 4.0%, volumetric 11.6%
One source: USDA Forest Products Laboratory, collected from the world literature (its Tables 5-5 and 4-4)
Why: From the USDA Wood Handbook, which collected these values from the world literature; Parana pine's density is worked from its specific gravity with the Handbook's own equations.
How much Parana pine moves
A 12 in wide flatsawn board of parana-pine that goes from 6% to 12% moisture content swells about 0.2 in (about 3/16 in, 5.1 mm). Quartersawn, the same board moves about 0.1 in (about 3/32 in, 2.5 mm). Flatsawn faces move 2 times as much as quartersawn ones, because the wood shrinks 7.9% around the growth rings but only 4.0% across them.
Worked from the Wood Handbook's shrinkage values (Table 4-4) with its Eq. 13-4; the Handbook gives no movement coefficients for imported woods. Individual boards vary: the Handbook gives shrinkage a coefficient of variation of about 15% (p. 4-11).
Color, grain and working
- Color
- Light or reddish-brown heartwood.
- Grain and texture
- Uniform texture with small pinhead knots on flatsawn faces; grain not interlocked, and no resin ducts or pitch.
- Working and character
- A softwood but not a true pine. Strong for its density, especially in shear, hardness and nail holding, but weak in compression across the grain; compression wood can make kiln-dried boards split and warp. Takes paint and glues easily.
- Uses
- Framing, interior woodwork, sashes and doors, furniture case goods and veneer.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-39.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Values for parana-pine from Wood Handbook Table 5-5b (p. 5-24), which the Handbook says were collected from the world literature, on clear, straight-grained specimens. Knots and cross grain make lumber weaker than these clear samples (Handbook Chapter 5).
| Property | Green | 12% MC |
|---|---|---|
| Bending strength (MOR) | 7,200 psi (50 MPa) | 13,500 psi (93 MPa) |
| Stiffness (MOE) | 1,350,000 psi (9.3 GPa) | 1,610,000 psi (11.1 GPa) |
| Crushing strength (compression parallel to grain) | 4,010 psi (28 MPa) | 7,660 psi (53 MPa) |
| Shear parallel to grain | 970 psi (7 MPa) | 1,730 psi (12 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 Wood Handbook prints 780 lbf of side hardness at 12% moisture content for parana-pine, a value it says was collected from the world literature (Table 5-5b, p. 5-24).
One source: USDA Forest Products Laboratory, collected from the world literature (its Tables 5-5 and 4-4) , 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, collected from the world literature (its Tables 5-5 and 4-4) , sources [1]
So
The Handbook gives only the green specific gravity (0.46) for parana-pine, so it is moved to 12% with the volumetric shrinkage of 11.6% (Eqs. 4-9 and 4-11), then multiplied by water's density and 1.12 (Eq. 4-14).
Arithmetic: exact by definition , sources [1]
The number
About 35 lb/ft³, or 2.9 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources