Tropical wood · Tropical America
Cow-tree wood
Cow-tree (Brosimum spp. (utile group), family Moraceae) is a tropical timber from tropical America. Dry, its Janka hardness is 903 lbf (4,017 N), and air-dry it weighs about 24–38 lb/ft³ (384–609 kg/m³). The figures are from the USDA Forest Products Laboratory's Tropical Timbers of the World, pp. 49–50.
Other names, by country: Mastate (Costa Rica), Avichuri (Colombia), Palo de vaca (Venezuela), Amapá doce, Caucho macho (Brazil).
Key numbers
- Janka hardness, dry
- 903 lbf (4,017 N)
- Green: 603 lbf (2,682 N)
- As printed: “Janka side hardness 603 lb for green material and 903 lb for air dry.”
- Air-dry density
- 24–38 lb/ft³ (384–609 kg/m³)
- Basic specific gravity
- 0.35–0.50 oven-dry weight, green volume
- As printed: “Basic specific gravity (ovendry weight/green volume) ranges from 0.35 to 0.50 for this group. Air-dry density averages about 24 to 38 pcf.”
- Shrinkage, green to oven-dry
- 7.8% tangential
- Radial 3.9%
One source: USDA Forest Products Laboratory, Tropical Timbers of the World (Chudnoff, 1979 edition), the only published source read for this wood
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE); crushing strength is compression parallel to the grain. The sheet collects these from published tests: it prints 2 data sets, from different tests and sources, so they can differ widely; all are shown, in the sheet's order, each at the moisture content printed beside it, never restated as 12%.
| Moisture | Bending strength (MOR) | Stiffness (MOE) | Crushing strength |
|---|---|---|---|
| Green | 8,490 psi (59 MPa) | 1.94 million psi (13.4 GPa) | 4,490 psi (31 MPa) |
| 12% MC | 14,310 psi (99 MPa) | 2.39 million psi (16.5 GPa) | 8,220 psi (57 MPa) |
A dash means the sheet prints no value; none is filled in.
What the data sheet says
- Color, grain and texture
- Dried there is no distinction between sapwood and heartwood, uniform yellowish-white to yellowish-brown or light brown. Grain is straight to widely and shallowly interlocked; medium texture; luster high. Odorless and tasteless.
- Working properties
- The wood is easy to machine. However, tension wood is sometimes prevalent and this will cause fuzzy grain and burning of saws due to pinching. Takes stains and finishes readily; presents no gluing problems.
- Durability
- The wood is vulnerable to attack by stain and decay fungi as well as insects.
- Uses
- Plywood, particleboard, fiberboard, carpentry, light construction, furniture components, pulp and paper products, and moldings.
- Where it grows
- Ranges from the Atlantic Coast in Costa Rica southward to Colombia and Ecuador.
Quoted from Tropical Timbers of the World, pp. 49–50, a USDA Forest Products Laboratory work in the public domain.
Work it out for your project
- Rank woods for furniture with the species picker
Weigh cow-tree against other woods on hardness, weight, movement and color, every figure from the Wood Handbook.