USDA Forest Service
Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53705-2398
Wood Technical Fact Sheet
Other Common Names: Aprono (Ghana), Bete (Ivory Coast), Ofun (Nigeria), Koul (Cameroon).
Distribution: Occurs in the deciduous forest type from ivory Coast to Cameroon.
The Tree: Reaches a height of 120 ft; bole clear and straight, buttressed, up to 60 ft in length; trunk diameters 2 to 3 ft.
General Characteristics: Heartwood yellow brown or dark gray brown, frequently with a purplish cast, often shows light and dark bands; sapwood whitish, sharply demarcated. Texture fine to medium; grain generally straight; luster low to medium. Resembles American black walnut. Lacks a distinct odor or taste.
Weight: Basic specific gravity (ovendry weight/green volume) 0.50 to 0.58; air-dry density 38 to 45 pcf.
Mechanical Properties: (2-cm standard)
Moisture content Bending strength Modulus of elasticity Maximum crushing strength
(%) (Psi) (1,000 psi) (Psi)
Green (9) 13,000 1,400 6,400
12% 17,700 1,580 8,500
12% (46) 17,200 1,680 7,750
12% (46) 14,900 1,450 7,150
Janka side hardness 1,210 lb for green and 1,290 lb for dry wood. Amsler toughness 150 to 324 in.-lb at 12% moisture content (2-cm specimen).
Drying and Shrinkage: Dries fairly rapidly with little degrade but knots tend to split and shake tends to extend. Kiln schedule T10-D4S is suggested for 4/4 stock and T8-D3S for 8/4. Shrinkage green to ovendry: radial 4.4%; tangential 7.3%; volumetric 10.2%. Movement in service is rated as medium.
Working Properties: Works easily with hand and machine tools with little dulling of cutters, has good nailing and gluing properties, rated as a good steam-bending wood. Sawdust may cause nose and throat irritation.
Durability: Heartwood is very durable and highly resistant to termite attack.
Preservation: Heartwood extremely resistant to preservative treatments; sapwood is permeable.
Uses: High quality cabinet and furniture work, joinery, turnery, decorative veneers Bark contains a cardiac poison of the digitalis group. Used as an alternate for walnut.
Additional Reading: (3), (9), (46)