Sapeli

Sapeli (Entandrophragma cylindricum)

African mahogany, abudicoro, sapeli

General characteristics:

It is a very large tree, reaching about 45 m in height and about 2.0 m in diameter (above the butt). It is found in the west coast region of Africa. Sapwood is yellowish white and heartwood is pinkish just after felling, darkening to typically mahogany shades of blackish cinnamon maroon. The pattern is delicately marked.

Origin:

Sapeli trees are found in rainforests in west and central Africa – from the Ivory Coast, through Ghana and Nigeria, to Cameroon, as well as in Uganda and Tanzania.

Tree habit:

Sapeli are large trees up to 45 m in height and with trunk diameters of up to 2 m or more. The trunks are straight and up to a considerable height devoid of branches (15-25 m). An advantage that facilitates working and increases material yield is the regular, cylindrical shape of the trunk, from which the second part of the species' Latin name, cylindricum, is derived.

Structure type:

Diffuse-vascular, large vessels mainly distributed singly or 2-3 at a time in radial clusters.

Sapwood:

Narrow (7 to 10 cm wide), yellowish-white in colour.

Heartwood:

When freshly sawn, it has a pinkish cinnamon colour and gradually darkens under the influence of light and the oxygen in the air to a reddish-brown colour typical of mahogany wood.

Fragrance:

Fresh wood has an intense lemony aroma similar to that of cedar wood, then gradually fades away

Pattern:

Annual increments are poorly distinguishable or invisible. A characteristic feature is the striped twist of the fibres, perfectly visible on the radial cross-section, on which the fine shine formed by the narrow vascular rays can also be observed. On the other cross sections, these elements are not visible. In sapeli wood, a more complex (intricate) arrangement of fibres occurs. Particularly sought-after and expensive is the so-called "pommelle" sapeli, i.e. sapeli with a wavy fibre arrangement, giving a very decorative pattern (dashed). The medullary rays in sapeli are mostly non-uniform rays. The pattern of the wood is enriched by the large vessels, which are best outlined on longitudinal sections in the form of fine indentations (grooves). They are less visible in cross-section and are surrounded by paratracheal parenchyma in the form of narrow rings, sometimes unilateral or poor. The most extensive, but poorly visible macroscopically, is the parenchyma forming tangentially running strands (3 to 10 cells wide).  Very rarely there is a diffuse apotracheal parenchyma.

Typical defects:

Fibre twist.

Properties of Sapeli wood:

According to the six-grade density scale, African mahogany is a moderately heavy wood (grade III). The average density for the air-dry condition (for wood with a moisture content of approximately 12%) is 650 kg/m³. Sapeli wood has very good mechanical characteristics. The compressive strength (average 56 MPa), static crushing strength (average 114 MPa) and impact strength (average 70 MPa) are particularly favourable. Due to the striped twist of the fibres, this wood has a reduced tensile strength along the fibres and modulus of elasticity in this anatomical direction.

Similar species:

African mahoganies of the genus Entandrophragma, African mahogany sipo, African mahogany tiama, African mahogany kosipo and acajou, and mahoganies proper (American) of the genus Swietenia.

Drying:

African sapeli mahogany wood dries relatively quickly, but desorption cracks often develop during the process. Its seasoning is recommended.

Working:

Working is not problematic, but due to its high density and the presence of an intricate fibre system, it requires the use of suitable tools (e.g. saws with carbide or ceramic abrasive pads). Nevertheless, smooth and glossy surfaces can already be achieved when planing, which is facilitated by the compact structure.

Joining:

Making joints with metal fasteners (nails and screws) requires pre-drilling due to the danger of split. It is best to use single-component polyurethane adhesives for adhesive joints.  

Finishing:

Generally accepts paints and varnishes well; gum-resin substances can be a hindrance.

Intended use:

veneers, furniture, floors, doors, interior fittings, high quality joinery products, boatbuilding.

• Mechanical properties: Both manual and mechanical working is good. It exhibits good nailing and screwdriving properties and adheres well. With final working, a very smooth, high-quality surface can be achieved.
• Modulus of elasticity: 14.0 GPa
• Tangential shrinkage: 7.2%
• Radial shrinkage: 5.0%
• Specific gravity: 690 kg/m³ (12%)
• Durability: species resistant to destructive fungal attack
• Dry wood pests: resistant – risk limited to sapwood penetration
• Protections: class 3 – poorly-accepting
• In addition: not recommended contact with soil, medium resistance to external conditions, possible contact with high humidity