Amazaque

Amazaque (Guibourtia ehie)
Ovangkol, Mutenye, Anokye, Daniele

Origins:

Amazaque is found in western Africa – from Sierra Leone, through the Ivory Coast, to northern Ghana and central Nigeria, and in central Africa – from Equatorial Guinea to western Gabon and Congo. The species is most abundant in Cameroon, Côte d'Ivoire and Liberia and Nigeria.

Tree habit:

Mature trees can reach 30-45 m in height and 0.5-0.9 m in diameter at the butt, not including flutes. The latter reach a height of around 2 m. The length of the knotless zone is approximately 20-25 m.

Structure type:

Diffuse-vascular, the vessels are mainly distributed in clusters (2-3 each, less often singly or in fours). Within the groupings, the vessels are arranged one behind the other in a radial direction. There are an average of five vessels per 1 mm² of cross section. The diameter of the vessels varies from 0.11 to 0.16 mm (average 0.14 mm).

Sapwood:

4-7 cm wide, initially yellowish white, turning grey-brown in decayed wood when exposed to light.

Heartwood:

The colour depends on the growing conditions of the tree and varies from yellowish brown to chocolate brown. It is not a uniform pastel colour, as black streaks are present.     

Fragrance:

The wood gives off a characteristic earthy smell.

Pattern:

On longitudinal sections it is enriched by the presence of medullary rays. On the tangential section they take the form of fine, darker lines (0.4-0.6 mm) and on the radial section they form a distinct shine. These are homocellular rays. Amazaque wood most often contains various forms of fibre arrangement. Most often the fibres are either wavy or twisted, in a nested or striped pattern. The annual increment boundary is visible through continuous, narrow strands of parenchyma, running tangentially, as well as a slight change in vessel density at the end of the annual increments. There is also a paratracheal woody parenchyma in the form of: perivascular to winged and winged-streaked. There is also a small amount of diffuse apotracheal parenchyma, usually with thicker walls and directly adjacent to the medullary rays.   

Typical defects:

Intricate arrangement of fibres, mineral inclusions in the form of white flecks.  

Properties of Amazaque wood:

Amazaque wood is distinguished by considerable variability in density, depending on the growing conditions. According to a six-grade density scale, it can range from moderately heavy (Class III) to very heavy (Class I). The average density for the air-dry condition (for wood with a moisture content of 12% or more) is 800 kg/m³. According to Monnin's four-grade scale, it is moderately shrinkable wood (grade 2). It is also characterised by typical anisotropy of shrinkage. The ratio of unit total shrinkage in the tangential direction to that in the radial direction is approximately 2. The significant scatter in the values of the individual mechanical properties of Amazaque wood recorded is due to the significant variation in density of this material and the frequent presence of a wavy fibre pattern. For example, the bending strength ranges from 70 to 177 MPa and the tensile strength along the fibres from 59 all the way up to 190 MPa. The non-straight fibre course has a positive effect on shear and splitting strength. High variability also applies to dynamic and elastic properties.  
   

Working:

Hard tools are needed for working (high speed steel is not enough, carbide inserts are needed). The non-straight running of the fibres makes this process even more difficult, which is why, for example, when planing, it is advisable to use tools with a rake angle of up to 15°  

Joining:

For nails and screws, it requires pre-drilling. Amazaque wood sticks well.  

Finishing:

After finishing (sanding, polishing), smooth, shiny surfaces with high decorative qualities are obtained, which can be enhanced with non-matt lacquer coatings.

Intended use:

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

Availability
26 mm – KD – SE edged – FAS grade
52 mm – KD – SE edged – FAS grade

• Mechanical properties: Working difficult due to irregular fibres, slight dulling effect on tools due to mineral structures. Bonding good, nailing requires pre-drilling.
• Modulus of elasticity: 17 GPa
• Tangential shrinkage: 8.7%
• Radial shrinkage: 4.2%
• Specific gravity: 850 kg/m³ (12%)
• Durability: species resistant to destructive fungal attack
• Dry wood pests: resistant – risk limited to sapwood penetration
• Protections: class 3-4 – poorly or non-accepting
• In addition: contact with the ground not recommended, resistant to external conditions