Other Common Names: Yellowwood (South Africa), Wiriwiri, Mse, Mushunga (Tanzania), Musenene, Sapta (Uganda).
Distribution: Species supplying commercial timber are widely distributed in the highlands of East Africa, mainly in Kenya south to Zimbabwe.
The Tree: May attain a height of 100 ft or more with diameters mostly 1.5 to 2.5 ft.
General Characteristics: Uniform light yellowish brown with no clear distinction between sapwood and heartwood, sometimes showing red streaks due to presence of compression wood. Texture very fine and even; grain straight; growth rings usually indistinct; resin ducts absent.
Weight: Basic specific gravity (ovendry weight/green volume) 0.43; air-dry density 32 pcf.
Mechanical Properties: (First set of data based on the 2-cm standard; second set on the 2-in. standard.)
Moisture content Bending strength Modulus of elasticity Maximum crushing strength
(%) (Psi) (1,000 psi) (Psi)
Green (40) 6,950 880 3,200
12% 11,900 1,170 6,250
12% (1) 10,230 1,385 6,470
Janka side hardness 560 lb for green material and 830 lb for dry.
Drying and Shrinkage: Dries fairly rapidly with some checking and a pronounced tendency to warp. Distortion can be minimized if the timber pile is weighted. Kiln schedule T2-D4 is suggested for 4/4 stock and T2-D3 for 8/4. Shrinkage green to ovendry: radial 2.8%; tangential 5.1%. Movement in service is rated as small.
Working Properties: Easy to work with hand and machine tools, takes an excellent finish, shapes and turns well, glues easily, easy to veneer, moderate steam- bending properties.
Durability: Heartwood has low durability and liable to termite damage as well as other insect attack.
Preservation: Easy to treat, open-tank treatments result in preservative oil absorptions of 14 to 25 pcf. Retentions of around 40 pcf can be obtained with a pressure treatment.
Uses: General construction, joinery, millwork, furniture components, boxes and crates, food containers, utility plywood.
Additional Reading: (1), (3), (6), (40)
1. Banks, C. H. 1954. The mechanical properties of timbers with particular reference to those grown in the Union of South Africa. J. S. African For. Assoc. 24:44-65.
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.
6. Chalk, L., J. B. Davy, H. E. Desch, and A. C. Hoyle. 1933. Twenty West African timber trees. Clarendon Press. Oxford.
40.Lavers, G. M. 1967. The strength properties of timbers. For. Prod. Res. Bul. No. 50. H. M. Stationery Office. London.
From: Chudnoff, Martin. 1984. Tropical Timbers of the World. USDA Forest Service. Ag. Handbook No. 607.