USDA Forest Service
Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53705-2398
(608) 231-9200

 

Wood Technical Fact Sheet

 

 Protium spp.

Kurokai

Copal

Family: Burseraceae

Other Common Names: Latilla, Pom (Mexico), Alcanfor, Fontole (Honduras), Carano, Chutra (Panama), Anime, Carano (Colombia), Balsamo, Tacamahaco (Venezuela), Kurokai (Guyana), Bois encens (French Guiana), Breu branco, Breu preto, Sucuriuba (Brazil).

Distribution: Throughout tropical America but most abundantly represented in the Amazon basin; frequent in the marsh forests of Guyana.

The Tree: Usually up to 90 ft in height; diameters mostly 16 to 20 in., sometimes up to 40 in. Some species with low, flat buttresses and fluted boles.

The Wood:

General Characteristics: Heartwood brown or reddish brown, sometimes with irregularly spaced darker brown lines; not always sharply demarcated from the pale buff to pinkish sapwood. Texture varies from rather fine to fairly coarse; luster rather high; grain straight to very irregular and interlocked; dry specimens without distinctive odor or taste. Silica reported for some species.

Weight: Basic specific gravity (ovendry weight/green volume) varies with species from 0.45 to 0.61; air-dry density 33 to 45 pcf.

Mechanical Properties: (First set of data based on the 2-cm standard, the second set on the 2-in. standard, and the third set on the 1-in. standard.)

Moisture content Bending strength Modulus of elasticity Maximum crushing strength

(%) (Psi) (1,000 psi) (Psi)

Green (42) 11,000 1,465 5,280

12% 16,850 1,765 9,200

Green (40) 9,300 1,510 4,370

12% 11,800 1,650 6,960

12% (24) 15,700 1,860 8,700

Janka side hardness at 12% moisture content ranged from 720 lb to 1,280 lb. Forest Products Laboratory toughness at 12% moisture content is 167 in.-lb (5/8- in. specimen).

Drying and Shrinkage: Reports vary from fairly easy to air-dry to moderately difficult. Kiln schedule T3-C2 is suggested for 4/4 stock and T3-C1 for 8/4. Shrinkage green to ovendry: radial 4.2%; tangential 6.8%; volumetric 10.7%.

Working Properties: Logs should be debarked prior to sawing to avoid resin accumulation on cutters and equipment. Dry wood works easily and rates fair to good in all operations. Cuts easily into veneers but tends to buckle on drying. Some species abrasive because of silica content.

Durability: Generally reported to have low resistance to attack by decay fungi and vulnerable to dry-wood termites. No appreciable resistance to marine borers.

Preservation: Generally heartwood is reported as difficult to treat with pressure-vacuum systems; sapwood is responsive.

Uses: Furniture, millwork, veneer and plywood, general construction, particleboard, possible substitute for birch. incense-like resin obtained from wounds to the bark and marketed as "elemi."

Additional Reading: (24), (40), (42), (46)