Cumaru

Cumaru (Dipteryx odorata)

Coumarou, tokabonnem, bob tonka, tonquin

General characteristics:

also commonly referred to as Brazilian teak or golden teak.
It is a high-quality wood with a hardness similar to IPE grade. The olive-brown colouring sometimes shifting to shades of dark cherry (depending on the habitat and growing conditions) and the moderate cost make Cumaru decking an attractive alternative to species such as Teak or Ipe. Cumaru board is resistant to fungi and decay processes. Cumaru decking board is an excellent alternative for those looking for wood with a rich grain.
 

Origin:

Cumaru trees are most commonly found in humid equatorial forests on loose permeable substrate (sand and gravel). The relatively wide distribution area of these trees is mainly in the south-western part of South America – from Venezuela and Colombia, through Brazil to Guyana, Suriname and French Guiana.

Tree habit:

Full-grown Cumaru timber is harvested from mature trees that, under favourable growth conditions, reach heights of 20-30 m, with trunk diameters of 0.5 to 0.7 m and even up to 1.1 m. The straight trunk, with a regular cylindrical shape, does not form extensive flutes.

Structure type:

Diffuse-vascular, vessels mainly distributed singly or in clusters (2-3 each), visible to the naked eye (0.1 to 0.25 mm in diameter). There are an average of 5 to 10 vessels per 1 mm² of cross-section.

Sapwood:

Narrow (2 to 3 cm wide), whitish-yellow in colour.

Heartwood:

Shortly after cutting, heartwood is a very distinct reddish-brown colour with lighter, sometimes yellowish-brown vessel lines. Under the influence of atmospheric agents (e.g. sunlight), it darkens intensively and takes on a rusty brown colour.

Fragrance:

The wood emits a characteristic pleasant smell (referred to in its Polish name).

Pattern:

Increment boundary unclear or completely invisible. The vessels are surrounded by a paratracheal winged or winged-streaked parenchyma, which sometimes takes a unilateral form. In this wood there is an irregular arrangement of fibres; the characteristic element forming the pattern of Cumaru wood is the stratified structure, delicately outlined on the tangential cross-section in the form of evenly spaced rows of single-row, homogeneous medullary rays. 

Typical defects:

fibre twist, colour change.

Properties of Cumaru wood:

According to the Cumaru six-grade density scale, it is a very heavy wood (Class I). The average density in the air-dry state (wood with a moisture content of approximately 12%) is 1080 kg m³. The high density of Cumaru wood has a beneficial effect on its mechanical properties. Similarly, the modulus of elasticity of the species in question is at a high level.

Similar species:

calata, light balau. 

Drying:

If carried out naturally, it proceeds relatively slowly. The problem arises with artificial drying, as the wood then tends to crack. Gentle drying programmes should be used to reduce the formation of desorption defects during artificial drying.

Working:

Cumaru is difficult to machine due to the frequent presence of an intricate fibre arrangement, as well as its high density and hardness. Cutting requires the use of specialised tools. In spite of this, smooth and even surfaces are obtained after finishing, and no harmful effects of wood dust have been reported.

Joining:

Cumaru is quite easy to join with screws, but only after pre-drilling. Bonding is hampered by the presence of oily substances and a dense structure, which reduces adhesion.

Finishing:

Not difficult

Intended use:

Light Bangkirai wood in the countries of harvest has quite a wide range of uses. The high natural durability of this material allows it to be used for external structures, including elements working in contact with water and soil (railway sleepers, bridge piles). It is also a boatbuilding wood used to make the sleepers of vessels. On land, it is often an industrial surface subject to heavy use (loading ramps, floors in wagons and containers). In Poland, light Bangkirai is available primarily in the form of various types of decking boards – one-side finely grooved and both-side grooved. The wood can also be used to make garden furniture.

We offer Cumaru grade decking in the following profiles:
- 21x145 mm – one side finely grooved / other side smooth