USDA Forest Service
Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53705-2398
(608) 231-9200

 

Wood Technical Fact Sheet

 

 Couma macrocarpa

Cow Tree

Family: Apocynaceae

Other Common Names: Perillo negro, Avichuri (Colombia), Guaimaro macho, Vacahosca (Venezuela), Dukaballi (Guyana), Ama-apa (Surinam), Leche-caspi (Peru), Cuma assu, Sorva (Brazil].

Distribution: An Amazonian species but also found in the Carare-Opon and Serrania de San Lucas regions of the Rio Magdalena in Colombia. Found mostly in low areas.

The Tree: Total tree heights 60 to 80 ft, with trunk diameters of 20 to 24 in.; straight, well formed stems.

The Wood:

General Characteristics: 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.

Weight: Basic specific gravity (ovendry weight/green volume) 0.50, air-dry density 38 pcf.

Mechanical Properties: (First set of data based on 2-cm standard; second set based on 2-in. standard).

Moisture content Bending strength Modulus of elasticity Maximum crushing strength

(%) (Psi) (1,000 psi) (Psi)

12% (21) 16,700 NA 9,280

12% (20) 15,900 NA 7,100

Janka side hardness 980 lb at 12% moisture content.

Drying and Shrinkage: This wood is easy to both air-dry and kiln-dry with little or no degrade due to warping or checking. No kiln schedules available. Shrinkage green to ovendry: radial 3.9%; tangential 6.4%; volumetric 10.4%.

Working Properties: The wood is easy to work with all tools, however there is some difficulty to generate smooth surfaces on quartersawn stock due to the interlocked grain. Easy to nail and screw.

Durability: Natural durability is low and prone to attack by blue-stain fungi.

Preservation: No data available but suggested uses in Colombia indicate the wood is responsive to preservation treatments.

Uses: Interior millwork, general construction, furniture components, veneer for plywood, particleboard and fiberboard, boxes, and crates.

Additional Reading: (20), (21), (56), (71)