Doussié

Doussié is a timber produced by various tree species of the genus Afzelia growing in tropical Africa.

Introduction and origin: doussié

Doussié is the common name and trade name covering the following botanical names: Afzelia bipindensis, bella, africana or pachyloba, of the Caesalpiniaceae family. However, it is bipindensis that is most highly valued — in fact red doussié.

The natural range of this species lies mainly in West and Central Africa, notably in Cameroon, Gabon, Nigeria, Senegal, Ghana and Côte d'Ivoire.

The tree has an average height of between 30 and 40 metres for a diameter varying from 0.6 to 1 metre, yielding logs of up to 20 metres (common lengths are between 6 and 12 metres).

It has broad buttresses at the base, sometimes rising to 2 metres. The thick, scaly bark is greyish.

This species is generally found in rainforest.

Appearance: doussié

Doussié has clearly distinct heartwood and sapwood. The heartwood is light ochre, turning reddish brown on exposure, while the pale yellow to whitish sapwood does not exceed 5 cm. The figure of doussié is not very pronounced: the veining is sometimes interlocked. The texture is medium and the grain is generally straight.

Occasionally, however, specimens with slight cross grain are found. The texture of the wood is even, as with the majority of tropical species. Yellow or white deposits are present in the pores and splits.

It has a characteristic leather smell. It is a hard, heavy wood with an average density ranging from 0.62 to 0.95 at 12% moisture content.

Main characteristics: doussié

The heartwood is naturally very durable and requires no preservative treatment, whether it stays dry or is in permanent contact with moisture. It can therefore be used whatever the biological hazard class (I to IV).

The volumetric shrinkage of doussié ranges from 0.34 to 0.54% per % of moisture content, which makes it a stable wood in service. Its mechanical qualities are excellent and its hardness highly valued, making it ideal for parquet flooring and decking.

It stands up well to attack by acidic products and corrodes iron in damp conditions.

Applications: doussié

Doussié is today used mainly for parquet flooring and terraces or decking, on account of its high resistance to indentation. Its stability and hardness led to its selection for the track of the Bercy velodrome in Paris. It is also one of the favourite species of shipwrights: frames, planking and decks are frequently made from doussié.

This durable wood is valued for both exterior and interior joinery. Staircase manufacturers are likewise keen on it. Luxury interior and exterior panelling is also available. The furniture industry uses this wood to produce high-end items in solid wood or in the form of sliced veneer or marquetry.

Finally, some structural frames are built in doussié.

Advice on use and finishing: doussié

Drying is slow but poses no major problems and generates neither heavy shrinkage nor damage: the risk of splits, distortion or surface checking is very low. Machining calls for special tooling: stellite-tipped blades, tungsten carbide tools. Sawing requires regular sharpening because of the hardness of the wood. Slicing behaviour is good.

Pre-drilling is recommended, as the species is fairly prone to splitting. Sanding is satisfactory. Gluing requires some care because of the hardness and the presence of resins. These can interfere with the finishing stages, and grain filling is recommended. Doussié dust can cause some irritation.

Doussié, surprising as it may seem, is highly valued for building velodrome tracks. It is one of the most stable woods, with very low shrinkage. What is more, it is barely affected by variations in ambient humidity. That makes this use easier to understand.

The Bercy Velodrome, built in 1989, was the first indoor track to use doussié, and also the best-performing wooden track ever built. It took 100 m³ of timber from Cameroon and 75 km of battens, assembled with nails, to build this remarkable 250 m track.