What is okan?
The Wood Guide · The wood register
Tropical hardwood · referenceOkan
Sixty metres tall and a trunk up to three metres thick. A giant from the West African forests that yields wood nothing gets through.
- Cylicodiscus gabunensis
- Up to 60 m tall
- Trunk up to 3 m thick
Okan
Sixty metres tall and a trunk up to three metres thick. A giant from the West African forests that yields wood nothing gets through.
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Okan in brief
One of the largest trees of the West African rainforest, and the source of one of the hardest hardwoods on the market.
The dimensions alone are remarkable: a height of up to sixty metres and a trunk diameter of up to three metres. Trees like that are centuries old, and that is exactly what gives the wood its density.
The wood is golden brown to reddish brown and is among the heaviest traded. Where most hardwoods reach their limit — permanent ground contact, heavy wear, mechanical load — okan is only just getting started.
Okan is a civil engineering timber: sheet piling, bridge decks, fender works, lock gates and heavy floors. You rarely see it in a private garden, and rightly so — it is too heavy and too coarse for that.
- Botanical
- Cylicodiscus gabunensis
- Origin
- West Africa
- Height
- up to 60 metres
- Trunk diameter
- up to 3 metres
- Colour
- golden brown to reddish brown
- Strength in
- density and wear resistance
Fair is fair: okan is hard to work and heavy to carry. Pre-drilling is a must, saw blades wear quickly, and the dust can irritate the skin and airways. It is not a pleasant material for DIY work.
Why it makes the grade for hydraulic engineering
Extremely dense
Among the heaviest commercial timbers. Water barely penetrates it, and without water there is no fungus.
Very hard-wearing
A bridge deck or industrial floor in okan withstands heavy loads for years without wearing down.
High durability
Even in ground contact and in water, where most species give up.
High bending strength
Large spans without deflection — the reason it is used in bridges.
What okan is used for
| Use | Why okan | Alternative |
|---|---|---|
| Sheet piling and bank revetments | Durable in permanent ground contact | Azobé, bilinga |
| Bridge decks | Bending strength and wear resistance | Azobé, ipé |
| Lock gates and fender works | Mass and resistance | Azobé, bilinga |
| Industrial floors | Extreme wear resistance | Jatoba, massaranduba |
| Railway sleepers | Load-bearing capacity and service life | Azobé, concrete |
| Garden furniture | Unsuitable — too heavy and coarse | Teak, acacia |
Frequently asked questions about okan
How big does an okan tree grow?
Up to sixty metres tall with a trunk diameter of up to three metres. It is one of the largest trees of the West African rainforest.
What is okan used for?
Mainly in hydraulic engineering and heavy construction: sheet piling, bridge decks, lock gates and industrial floors. It is too heavy and too coarse for garden furniture.
Is okan the same as azobé?
No, but it plays in the same league. Azobé is Lophira alata, okan is Cylicodiscus gabunensis — both extremely heavy and both hydraulic engineering timbers.
Can I work okan myself?
With carbide-tipped tools and pre-drilled holes, yes, but it is not easy. The dust can also cause irritation — work with extraction and a mask.
Okan in perspective
A reference species in our register — the wood of bridges and sheet piling.
Have a question about your project? Just ask — we're happy to help.
Photos via Wikimedia Commons: Cylicodiscus gabunensis — Cirad, Xylothèque (via Gallica/BnF), Public domain · Cylicodiscus gabunensis — Cirad, Xylothèque (via Gallica/BnF), Public domain