Tropical wood · Tropical America
Couma macrocarpa wood
Couma macrocarpa (Couma macrocarpa, family Apocynaceae) is a tropical timber from tropical America. Dry, its Janka hardness is 980 lbf (4,359 N), and air-dry it weighs about 38 lb/ft³ (609 kg/m³). The figures are from the USDA Forest Products Laboratory's Tropical Timbers of the World, pp. 101–102.
Other names, by country: Perillo negro, Avichuri (Colombia), Guaimaro macho, Vacahosca (Venezuela), Dukaballi (Guyana), Ama-apa (Surinam), Leche-caspi (Peru), Cumá assú, Sorva (Brazil).
Key numbers
- Janka hardness, dry
- 980 lbf (4,359 N)
- As printed: “Janka side hardness 980 lb at 12% moisture content.”
- Air-dry density
- 38 lb/ft³ (609 kg/m³)
- Basic specific gravity
- 0.50 oven-dry weight, green volume
- As printed: “Basic specific gravity (ovendry weight/green volume) 0.50, air-dry density 38 pcf.”
- Shrinkage, green to oven-dry
- 6.4% tangential
- Radial 3.9%, volumetric 10.4%
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 |
|---|---|---|---|
| 12% MC | 16,700 psi (115 MPa) | — | 9,280 psi (64 MPa) |
| 12% MC | 15,900 psi (110 MPa) | — | 7,100 psi (49 MPa) |
A dash means the sheet prints no value; none is filled in.
What the data sheet says
- Color, grain and texture
- Wood cream-colored or pale brown, often with a pinkish tinge; no sharp demarcation between sapwood and heartwood. Grain fairly straight to interlocked; texture medium; luster rather low to medium; odor and taste not distinctive. COW TREE
- Working properties
- The wood is easy to work with all tools, however there is some difficulty to generate smooth surfaces on quarter-sawn stock due to the interlocked grain. Easy to nail and screw.
- Durability
- Natural durability is low and prone to attack by blue-stain fungi.
- Uses
- Interior millwork, general construction, furniture components, veneer for plywood, particleboard and fiberboard, boxes, and crates.
- Where it grows
- An Amazonian species but also found in the Cararé-Opón and Serrania de San Lucas regions of the Rio Magdalena in Colombia. Found mostly in low areas.
Quoted from Tropical Timbers of the World, pp. 101–102, 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 couma macrocarpa against other woods on hardness, weight, movement and color, every figure from the Wood Handbook.