Cumaru
| Family | Leguminosae (Fabaceae) |
| Botanical Names | Dipteryx alata Vogel |
| Continent | Latin America |
| CITES | (Washington convention of 2017)
No trade Restrictions |
| Diameter | 50 to 90 cm |
| Thickness of Sapwood | 2 – 3 cm |
| Buoyancy | Does not float |
| Log Conservation | Good |
Wood Description
| Reference colour | Sapwood | Texture | Grain | Interlocked grain | Notes |
|---|---|---|---|---|---|
| Red brown | Clearly demarcated | Medium | Interlocked grain | Marked | Unpleasant wood odour when green. Heartwood varies from yellow brown to reddish brown with darker thin veins |
Flat Sawn
Quarter Sawn
Physical and Mechanical properties
| Property | Mean Value |
|---|---|
| Density* | 1.07 |
| Monnin hardness* | 13.1 |
| Coefficient of volumetric shrinkage | 0.73 % per % |
| Total tangential shrinkage (Ts) | 7.7 % |
| Total Radial shrinkage (Rs) | 5.5 % |
| T/R anisotropy ratio | 1.4 |
| Fibre Saturation point | 22 % |
| Thermal conductivity | 0.34 W/(m.K.) |
| Lower heating value | 19,760 kJ/kg |
| Crushing strength* | 103 MPa |
| Static bending strength* | 170 MPa |
| Longitudinal modulus elasticity* | 26,610 MPa |
Natural durability & Treatability
| Resistance to decay | Class 1 – Very durable |
| Resistance to dry wood borers | Class D – durable (sapwood demarcated, risk limited sapwood) |
| Resistance to termites | Class D – Durable |
| Treatability | Class 4 – non-treatable |
| Use class covered by natural durability | Class 4 - in ground or freshwater contact |
Notes
This species is listed in the NF EN 350 standard. According to the European standard NF EN 335 of May 2013, performance length might be modified by conditions in which it is used.
Preservation Treatment
| Against dry wood borer attacks. | This wood does not require any preservation treatment. |
| In case of temporary humidification | This wood does not require any preservation treatment |
| In case of permanent humidification | This wood does not require any preservation treatment |
Sawing and Machining
| Blunting effect | Fairly high |
| Tooth for sawing | Stellite tipped |
| Machining tools | Tungsten carbide |
| Suitability for peeling | Not recommended or without interest |
| Suitability for slicing | good |
| Notes | Sawing and machining are difficult due to hardness and interlocked grain |
Drying
| Drying rate | Slow |
| Risk of distortion | Slight risk |
| Risk of case hardening | Yes |
| Risk of checking | High risk |
| Risk of collapse | No known specific risk |
| Notes | Drying must be done slowly. Risks of casehardening with thick material |
| Suggested drying schedule | Schedule # 9 |
Assembling
| Nailing/ Screwing | Good but pre – boring necessary. |
| Notes | Very high specific gravity: important that gluing be performed in compliance with the code of practice and instructions for the glue used. |
Cross sections of Dipteryx odorata
Commercial Grading
Sawn timber appearance grading
According to NHLA grading rules (2015) Possible grading: FAS, Select, Common 1, Common 2, Common 3 In French Guiana, the local name of this species is “Gaiac de Cayenne” . Grading is done according to local rules "Bois guyanais classes (1990)". Possible grading: Choice 1, choice 2, choice 3, choice 4
Fire Safety
| Conventional French grading | Thickness > 14 mm: M3 (moderately inflammable)
Thickness < 14 mm: M4 (easily inflammable) |
| Euroclass grading | D-s2, d0
Default grading for solid wood that meets requirements of European standard NF EN 14081-1 (April 2016): structural graded timber in vertical uses and ceilings with minimal mean density of 0.35 and minimal thickness of 22 mm. |
Visual structure grading
According to French standard NF B 52- 001-1 (2011) and associated national standards, strengths classes D40 can be provided by visual grading.
Main End uses
- Turned goods
- Heavy carpentar
- Ship building ( planking and deck )
- Tool handles (resilient woods )
- House framing
- Industrial or heavy flooring
- Stakes
- Slices veneer
- Decking
- Bridges (parts in contact with water or ground )
- Poles
- Cooperage
- Hydraulic works ( fresh water )
- Sleepers
Notes
Slicing : only with the best shapes timber , to obtain very decorative veneers