Tropical wood · Africa
Alstonia wood
Alstonia (Alstonia congensis, family Apocynaceae) is a tropical timber from Africa. Dry, its Janka hardness is 410 lbf (1,824 N), and air-dry it weighs about 25 lb/ft³ (400 kg/m³). The figures are from the USDA Forest Products Laboratory's Tropical Timbers of the World, pp. 325–326.
Other names, by country: Mujwa, Mujua (Uganda), Emien (Ivory Coast), Sindru (Ghana), Ahun, Awun, (Nigeria), Bokuk, Kanja (Cameroon), Kaiwi, Kauwi (Sierra Leone).
Key numbers
- Janka hardness, dry
- 410 lbf (1,824 N)
- Green: 370 lbf (1,646 N)
- As printed: “Janka side hardness 370 lb for green and 410 lb for dry material.”
- Air-dry density
- 25 lb/ft³ (400 kg/m³)
- Basic specific gravity
- 0.33 oven-dry weight, green volume
- As printed: “Basic specific gravity (ovendry weight/green volume) 0.33; air-dry density 25 pcf.”
- Shrinkage, green to oven-dry
- 5.4% tangential
- Radial 4.0%, volumetric 12.4%
One source: USDA Forest Products Laboratory, Tropical Timbers of the World (Chudnoff, 1979 edition), the only published source read for this wood
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE); crushing strength is compression parallel to the grain. The sheet collects these from published tests: it prints 3 data sets, from different tests and sources, so they can differ widely; all are shown, in the sheet's order, each at the moisture content printed beside it, never restated as 12%.
| Moisture | Bending strength (MOR) | Stiffness (MOE) | Crushing strength |
|---|---|---|---|
| Green | 5,220 psi (36 MPa) | 0.93 million psi (6.4 GPa) | 2,920 psi (20 MPa) |
| 12% MC | 8,560 psi (59 MPa) | 1.2 million psi (8.3 GPa) | 5,240 psi (36 MPa) |
| 12% MC | 7,000 psi (48 MPa) | 0.84 million psi (5.8 GPa) | 3,920 psi (27 MPa) |
A dash means the sheet prints no value; none is filled in.
What the data sheet says
- Color, grain and texture
- Wood yellowish-white with no distinction between sapwood and heartwood. Texture fine to medium; grain usually straight; luster low; without characteristic odor or taste. Large slitlike radial canals often occur at intervals of 1-3 ft.
- Working properties
- Works easily with both hand and machine tools and dresses to a smooth finish if sharp cutting edges are used. Glues and nails well; steam bending properties are poor.
- Durability
- Wood is highly perishable and should be converted rapidly or given a chemical dip to prevent stain; liable to termite attack as well as powder-post beetle attack.
- Uses
- Light construction, plywood core stock, boxes and crates, joinery, furniture components.
- Where it grows
- Widely distributed throughout West and Central Africa; abundant in humid forests of the Cameroons.
Quoted from Tropical Timbers of the World, pp. 325–326, a USDA Forest Products Laboratory work in the public domain.
Work it out for your project
- Rank woods for furniture with the species picker
Weigh alstonia against other woods on hardness, weight, movement and color, every figure from the Wood Handbook.