Cumaru

Cumaru is one of the heaviest woods in the world with the best durability for outdoor use. The tree species is native to the entire tropical distribution area of Central America and northern South America. Cumaru is best known for its tonka bean fruit with its medicinal properties(Wikipedia).

Compared to Bangkirai, Cumaru has so far played a minor role in Europe as a tropical precious wood. For a few years now, however, Cumaru has been used as a decking board due to its excellent technical properties. decking boards or substructure also becoming increasingly popular in Germany.

Cumaru – the South American teak

In the South American market, Cumaru is very popular for terraces on the roof, in the garden or by the swimming pool. Its richness of color, high durability and good surface are convincing. In North America, Cumaru is also known as “Brazilian teak”.

Unfortunately, this heavy and very durable wood is only available in small quantities from sustainable FSC® forestry in Europe. At Betterwood, however, all decking boards, construction timber and wooden tiles made from Cumaru are FSC®-certified. Cumaru is not subject to the protection guidelines of CITES.

The Cumaru tree can reach a height of up to 40 meters and its BHD can be between 0.6 and 1.5 m. The substitutes of Cumaru are Bongossi, bangkiraiOkan, Mukulungu, Moabi.

Cumaru – heavy and hard

Cumaru is a very heavy wood with an average density of 1200 – 1300 kg/m3 and a moisture content of 12%.

The high Janka hardness of 12,000 – 16,000 N makes Cumaru moderately dimensionally stable. Cumaru has a radial and tangential shrinkage rate of Rad 0.9% and Tan 1.2 % at a wood moisture content of 12%. This and its very high durability make Cumaru an ideal wood for outdoor use in load-bearing areas.

Cumaru is a very difficult wood to work with due to its hardness properties. Holes for nails or decking screws must be pre-drilled.

The relationship between stress and elongation, which the application of force produces on the elasticity of the wood, is measured in Cumaru with a MOE of 26610 N/mm2 and the bending and compressive strength up to break is the MOR is given as 103 N/mm2.

The durability class  of Cumaru is “Class 1” according to DIN-EN 350-2. This means that it is highly resistant to fungi -infestation. Its high resistance to drywood borers and termites also makes Cumaru the ideal garden wood.

Cumaru is very difficult to treat as it hardly absorbs any oil or wood primer. However, this is not relevant as Cumaru does not require any additional treatment against wood-discoloring and wood-destroying fungi or insects due to its natural durability properties. There is also a special decking oilthat has been specially developed for the care of tropical wood decking boards.

Cumaru as decking wood

Due to the positive properties mentioned above, the high durability, the high resistance to fungi and insects, Cumaru is very well suited as construction wood for the substructure of terraces.

Cumaru is also very popular in South America and increasingly in Germany for decking boards, both in the substructure and because of its beautiful appearance as decking boards themselves.

Due to its hardness properties, Cumaru can also be used as flooring in containers or trucks on surfaces subject to very heavy wear.

However, Cumaru is mainly used in load-bearing structures and wooden decking in outdoor areas such as gardens and landscaping.

Sources:

1. Dipteryx odorata (Aubl.) Willd., D. alata Vog. (Cumarú) ‘Richter, H.G., and Dallwitz, M.J. 2000 onwards. Commercial timbers: descriptions, illustrations, identification, and information retrieval. In English, French, German, Portuguese, and Spanish. Version: June 25th, 2009. 
2. Wikipedia, Dipteryx odorata
3. Wikipedia, Tonka bean
4. “Sarrapia – Dipteryx odorata” via @Humboldtina-Venezuela
5. Cumaru specifications via @tropix.cirad.fr
6. Cumaru via @GD-Holzhandel