Other Common Names: Achi, Ngu, Akolodo (Nigeria), Meblo (Ivory Coast), Naga (Cameroon), Mendou (Gabon).
Distribution: A commercial grouping of four species of Brachystegia found in West Africa; common and gregarious in the wetter high forests of Nigeria.
The Tree: Tall, emergent 120 to 150 ft in height, boles are straight and cylindrical, trunk diameter 4 to 7 ft above the buttresses.
General Characteristics: Heartwood light to dark brown; sapwood yellow to yellowish brown, well defined. Texture medium to coarse; grain usually deeply interlocked producing a pronounced roe figure; luster high.
Weight: Basic specific gravity (ovendry weight/green volume) varies with species 0.45 to 0.58; air-dry density 34 to 44 pcf.
Mechanical Properties: (2-cm standard)
Moisture content Bending strength Modulus of elasticity Maximum crushing strength
(%) (Psi) (1,000 psi) (Psi)
Green (42) 11,400 1,280 5,720
12% 15,200 1,530 8,270
12% (41) 12,300 1,190 6,230
Janka side hardness 930 to 1,430 lb for dry material.
Drying and Shrinkage: Dries rather slowly with a marked tendency to check and warp. Kiln schedule T6-D2 is suggested for 4/4 stock and T3-D1 for 8/4. Shrinkage green to 12% moisture content: radial about 2.5%; tangential about 3.5%. Movement in service is rated as medium.
Working Properties: Difficult to saw because of gumming of teeth, blunting may be serious, machines moderately well, good turning characteristics, difficult to plane to a smooth surface because of severe tearing of grain in B. nigerica.
Durability: Heartwood is rated as moderately durable, sapwood liable to attack by powder-post beetles.
Preservation: Heartwood is extremely resistant to treatment, sapwood is permeable.
Uses: Parquet flooring, decorative veneer, general construction where high durability is not required, joinery.
Additional Reading: (3), (9), (41), (42)
3. Bolza, E., and W. G. Keating. 1972. African timbers-the properties, uses, and characteristics of 700 species. CSIRO. Div. of Build. Res., Melbourne, Australia.
9. Farmer, R. H. 1972. Handbook of hardwoods. H. M. Stationery Office. London.
41. Nigeria: Dep. For. Res. 1966. Brachystegia kennedyi (Okwen). For. Prod. Res. Rep. Dep. For. Res. Nigeria No. FPRL/7.
42. Nigeria: Dep. For. Res. 1966. Brachystegia nigerica (Okwen). For. Prod. Res. Rep. Dep. For. Res. Nigeria No. FPRL/8.
From: Chudnoff, Martin. 1984. Tropical Timbers of the World. USDA Forest Service. Ag. Handbook No. 607.