Detailed Specs: Determa
Scientific Name: Sextonia rubra; Ocotea Rubra
Family: Lauraceae
Other Names: Wana, Wane (Suriname), Grignon rouge (French Guiana), Louro vermelho (Brazil)
The Tree
Reaches heights of 130 feet with diameters of 5 feet; usually 92-100 feet high with diameters of 2-3 feet; boles are generally basally swollen and clear 40-80 feet.
The Wood
General Characteristics: Heartwood is light reddish brown with a golden sheen. The sapwood is well defined, narrow, and dull grey or pale yellowish brown. It has a resemblance to African mahogany in terms of its coarse grain. The grain is interlocked to straight, quarter sawn lumber is sometimes attractively figured; dry wood is without a distinctive odor or taste.
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Weight: Basic specific gravity (oven dry weight/green volume) 0.52 to 0.59; air- dry Density 40-45 pcf.
Drying and Shrinkage: The wood is moderately difficult to air season: drying at a moderate rate with slight checking and moderate warp. Kiln schedule T6-D2 is suggested for 4/4 stock and T3-D1 for 8/4; for 8/4; there is a tendency to warp and check in the kiln. Shrinkage green to oven dry: radial 3.7%; tangential 7.6%; volumetric 10.4%.
Mechanical Properties: (First set of data based on the 2-cm standard; second on the 2-in. standard).
|
Moisture Content |
Bending Strength (psi) |
Maximum Crushing Strength (psi) |
Modules of Elasticity (1000 psi) |
| Green (74)
12% Green (30) 12% |
7,820
10,470 10,300 13,600 |
3,760
5,800 5,150 7,150 |
1,460 1,820 4,450 N/A |
Janka side hardness 520 lb for green material and 660 lb at 12% moisture content. Forest Products Laboratory toughness average
for green and dry material is 75 inches – pound (5/8 – inch specimen). Amsler toughness 137 in-lb at 15% moisture content (2-cm specimen).
Working Properties: Works readily with hand and machine tools with minimum dulling effect; reported to glue readily and polishes fairly well.
Durability: According to graveyard and pure culture tests determa’s heartwood is rated durable. It is resistant to attack by white- rot and dry-wood termites. It is also very resistant to moisture and has excellent weathering characteristics. The wood equals Honduras Mahogany in its resistance to termites and marine borers.
Distribution: The Guianas, Trinidad and the lower Amazon region. Occasional to frequent on Sandy or loamy soils in Guyana.
Preservation: The heartwood is not treatable.
Uses: This is generally a utility timber used for both interior and exterior qualities. Used for furniture, boat planking, tanks an d cooperage, joinery, heavy marine construction, turnery, parquet flooring, veneer and plywood.
References
– Chundnoff, Martin (1984), “Tropical Timbers of the World.” USDA Forest Service Ag. Handbook No.607.
