Samba

Samba (Triplochiton scleroxylon)

Obeche, Abachi, Ayous, Wawa.

Origin:

Samba is found in virtually all of West Africa – from Guinea and Liberia to Cameroon, and in smaller numbers in central Africa, such as the Democratic Republic of Congo. The species prefers the forests of the West African monsoon zone, representing a transitional form – from humid evergreen equatorial forests to dry savannas.

Tree habit:

Samba is a fast-growing tree species. Record-breaking specimens can reach a height of 50 m and a diameter of 2 m measured above narrow, board-like flutes that extend 6-8 m from the base of the trunk. The trunk shows little convergence and is branchless up to 30 m in height. The crown of the tree is usually spherical and dense.

Structure type:

Diffuse-vascular, the vessels are evenly distributed. These vessels are usually arranged singly, less often in pairs or threes, in radial rows. 

Sapwood:

Whitish-yellow in colour, often with grey streaks as a result of blue stain.

Heartwood:

Yellowish white to yellowish cream in colour, similar to sapwood.   

Fragrance:

The samba wood does not emit any characteristic odour.

Pattern:

The wide annual increments (often more than 1 cm) are only clearly visible on the cross-section. Large vessels can be seen as small pinholes on the cross-section and fine matted grooves on the longitudinal sections. The vessels are surrounded by narrow rings of paratracheal parenchyma, which also occurs as poor parenchyma. More extensive is the extravascular parenchyma, which occurs in scattered groupings across the width of the annual increment. Medullary rays are only visible on longitudinal sections. These are heterogeneous rays. On the radial cross-section, in addition to the shine, a striped twist of fibres is present in the form of regular, fine brightening or darkening of the wood surface. On the tangential section, a stratified structure is noticeable.

Typical defects:

Blue stain, fibre twist.

Properties of Samba wood:

According to the six-grade density scale, it is a very light wood (grade VI). Samba wood has an average moisture content of the fibre saturation point (approximately 29%). A favourable feature is the low shrinkage – according to Monnin's four-grade scale, it is a low-shrinkage wood (grade I). The low density of the wood is the cause of its relatively poor mechanical properties. The average bending strength is 73 MPa and the compressive strength along the fibres is 40 MPa. Due to the presence of the striped fibre twist, the tensile strength along the fibres is particularly low (49 MPa on average) and every other strength is characterised by a high variability. In terms of mechanical properties, samba wood is similar to domestic poplar wood.

Similar species:

Koto (Pterygota), Framire, Limba and Balsa.

Drying:

The low shrinkage and porous structure of the wood promote rapid drying, and the wood has no tendency to warp or crack.

Working:

Easy, helped by the low density. A particularly smooth cut is obtained when sawing with saws with extended and widened teeth. The dust generated during working can cause skin irritation in some people. This wood allows even complex milled profiles and joints.

Joining:

Easy, whether using adhesives or metal fasteners, with no drilling required.  

Finishing:

coating with paint and varnish, once the wood pores have been filled, does not cause problems.

Intended use:

doors, plywood, furniture filling, sauna structures

Availability

26 mm – KD – SE edged – FAS grade

52 mm – KD – SE edged – FAS grade

• Mechanical properties: Working is not difficult; bonding is good; nailing does not require pre-drilling.
• Modulus of elasticity: 7.3 GPa
• Tangential shrinkage: 5.0%
• Radial shrinkage: 2.9%
• Specific gravity: 380 kg/m³ (12%)
• Durability: species not resistant to destructive fungal attack
• Dry wood pests: not resistant
• Protections: class 1 – well-accepting