Obeche (Triplochiton scleroxylon) in numbers: hardness, weight, strength, shrinkage, movement and decay resistance, taken from the tables of the USDA Forest Products Laboratory’s Wood Handbook, followed by what the wood is like to work and what it is used for. The values are averages from small, clear, straight-grained test specimens; real boards with knots, sloping grain or a different moisture content will differ.
| Property | Obeche |
|---|---|
| Janka side hardness, 12% moisture | 430 lbf (1,913 N) |
| Janka side hardness, green | 420 lbf |
| Hardness rank | harder than 18 of the 168 woods with a 12% hardness value in our database |
| Density at 12% moisture | 24.0 lb/ft³ (385 kg/m³)† |
| Weight per board foot (12%) | 2.00 lb† |
| Specific gravity (ovendry weight, green volume) | 0.3 |
| Specific gravity at 12% moisture | 0.34† |
| Bending strength (modulus of rupture), 12% | 7,400 psi |
| Stiffness (modulus of elasticity), 12% | 0.86 million psi |
| Crushing strength (compression parallel to grain), 12% | 3,930 psi |
| Shrinkage green to ovendry: radial / tangential / volumetric | 3.0% / 5.4% / 9.2% |
| Tangential / radial shrinkage ratio | 1.8 |
| Dimensional change per 1% moisture (radial / tangential) | 0.00106 / 0.00183 |
| Heartwood decay resistance | slightly or nonresistant |
What it is
Obeche (Triplochiton scleroxylon) trees of west-central Africa reach 150 ft or more in height and up to 5 ft in diameter, and the trunk is usually free of branches for a long way, so clear lumber in large sizes is available. In Europe it is better known as ayous or abachi, and in Ghana as wawa.
The wood is creamy white to pale yellow with little or no difference between sapwood and heartwood. It is fairly soft, of uniform medium to coarse texture, and the grain is usually interlocked but sometimes straight.
Working properties
Obeche is one of the lightest commercial hardwoods: about 24.0 lb per cubic foot at 12% moisture content, with a Janka hardness of 430 lbf. It dries readily with little degrade, is easy to work and machine, veneers and glues well, and takes nails and screws without splitting. Sharp edges matter, as soft fibres crush rather than cut with a dull tool.
It is not resistant to decay, and green sapwood is subject to blue stain; it is in the slightly or nonresistant class of Table 14-1. Low density also means low thermal conductivity (Wood Handbook chapter 4: conductivity rises with specific gravity), so obeche feels warm rather than hot to the touch, which is why it is a favourite for sauna benches and wall boards.
Weight and density
At 12% moisture content obeche weighs about 24.0 lb per cubic foot (estimated from its specific gravity and shrinkage), so one board foot (144 cubic inches) weighs about 2.00 lb. An 8 ft board of actual size 3/4 × 5-1/2 in. (a 1×6) holds 0.229 cubic feet and weighs about 5.5 lb; an 8 ft piece 1-1/2 × 3-1/2 in. (a 2×4 size) weighs about 7.0 lb. Green wood is much heavier because of the water it holds.
Density here is ovendry weight plus 12% water, divided by volume at 12% moisture content (Wood Handbook Eq. 4-12: density = specific gravity at 12% × 62.43 lb/ft³ × 1.12).
Wood movement
The Wood Handbook gives dimensional change coefficients for each species: the fraction of its width a board gains or loses for every 1% change in moisture content, between about 6% and 14%. For obeche they are 0.00183 across a flatsawn face (tangential) and 0.00106 across a quartersawn face (radial).
Worked example: a flatsawn board 7-1/4 in. wide (a nominal 1×8) that goes from 6% moisture content in a heated winter house to 12% in a humid summer changes width by 7.25 × 0.00183 × 6 = 0.08 in. (about 3/32 in.). The same board quartersawn moves 0.046 in. (about 1/32 in.). Allow for this in panels, tabletops and floors; the wood movement calculator works it out for any size and moisture range.
How it compares
| Species | Janka (lbf) | Density (lb/ft³) | Bending (psi) | Stiffness (Mpsi) | Tangential shrink (%) | Decay resistance |
|---|---|---|---|---|---|---|
| Obeche | 430 | 24.0† | 7,400 | 0.86 | 5.4 | slightly or nonresistant |
| American basswood | 410 | 25.9 | 8,700 | 1.46 | 9.3 | slightly or nonresistant |
| Okoume | 380 | 24.8* | 7,400 | 1.14 | 6.1 | slightly or nonresistant |
| Balsa | — | 12.0* | 3,140 | 0.49 | 7.6 | slightly or nonresistant |
| Eastern white pine | 380 | 24.5 | 8,600 | 1.24 | 6.1 | moderately resistant (old growth only); otherwise slightly or nonresistant |
| Yellow-poplar | 540 | 29.4 | 10,100 | 1.58 | 8.2 | slightly or nonresistant |
Uses
The Handbook calls obeche especially suitable for veneer and corestock. Other uses include furniture components, millwork, blockboard, boxes and crates, particleboard and fiberboard, patterns and artificial limbs. Thin obeche sheet is also a classic material for model aircraft.
Frequently asked questions
Why is obeche used in saunas?
Light woods conduct heat slowly, so a low-density wood like obeche stays comfortable to touch at sauna temperatures. It is also free of resin and easy to work.
How heavy is obeche?
About 24.0 lb per cubic foot at 12% moisture content in the Handbook data, or 2.00 lb per board foot.
Is obeche a hardwood?
Yes, botanically, but with 430 lbf of Janka hardness it is softer than most softwoods.
Is obeche rot resistant?
No. Use it indoors or in dry conditions only.
Sources
- USDA Forest Products Laboratory. Wood Handbook: Wood as an Engineering Material. General Technical Report FPL-GTR-190, 2010. Chapter 2 (species descriptions), Chapter 4 (Tables 4-3, 4-4 shrinkage; Eq. 4-7, 4-9, 4-12 density), Chapter 5 (Tables 5-3b, 5-5b strength and hardness), Chapter 13 (Table 13-5 dimensional change coefficients), Chapter 14 (Table 14-1 decay resistance)
- USDA Forest Products Laboratory. Wood Handbook, 2021 edition (FPL-GTR-282)
Last reviewed: 24 October 2026. Numbers are generated from our parsed copy of the Handbook tables, so every page uses the same data. Values marked * are estimates computed with the Handbook’s own equations. Spotted an error? Please let us know.