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


Wood Technical Fact Sheet


 Uapaca spp.


Family: Euphorbiaceae

Other Common Names: Abo emido, Yeye (Nigeria), Rikio, Borikio, Rikio riviere (Ivory Coast, Cameroon).

Distribution: Tropical areas of West Africa, mostly in swampy regions but may also border on the savanna.

The Tree: May reach a height of 90 ft; bole generally straight and may be 40 ft in length; trunk diameters 2 to 3 ft; high stilt roots.

The Wood:

General Characteristics: Heartwood pale red, red brown, or chocolate brown; sapwood paler, usually not clearly demarcated. Texture mostly medium to coarse; grain generally straight; little luster. High silica content.

Weight: Basic specific gravity (ovendry weight/green volume) 0.54 to 0.65; air- dry density 40 to 52 pcf.

Mechanical Properties: (2-cm standard)

Moisture content Bending strength Modulus of elasticity Maximum crushing strength

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

12% (47) 15,300 1,600 7,400

12% (44) 15,300 NA 8,050

12% (44) 20,400 2,580 8,200

Amsler toughness 150 to 265 in.-lb at 12% moisture content (2-cm specimen).

Drying and Shrinkage: Generally care is required in seasoning, best results if quartersawn, logs should be converted soon after extraction to minimize shake and checking. No information on kiln schedules. Shrinkage green to ovendry: radial 4.6 to 6.0%; tangential 9.3 to 11.4%; volumetric 13.2 to 16.0%.

Working Properties: Timber saws with some difficulty due to silica, generally finishes well and glues satisfactorily.

Durability: Heartwood moderately durable to highly so and moderately resistant to termite attack.

Preservation: Heartwood resistant to pressure treatments; sapwood mostly permeable.

Uses: Good fuel and charcoal wood, light construction, boatbuilding, flooring. Fruits are edible.

Additional Reading: (3), (44), (47)