Shorea spp.

Balau group

Family: Dipterocarpaceae

Other Common Names: Red Selangan Batu (Sabah), Guijo (Philippines), Balau Merah, Membatu (Malaya), Balau Merah (Indonesia).

Distribution: Malay Peninsula including Indochina, Indonesia, Philippines; often in almost pure stands.

The Tree: Reaches a height of 200 ft, boles straight and regular; trunk diameters to 6 ft over large buttresses.

The Wood:

General Characteristics: Heartwood light to deep red brown; sapwood lighter in color, not always sharply demarcated. Texture moderately fine to slightly coarse; grain typically interlocked; without characteristic odor or taste; rather dull; resin canals with white contents in concentric lines on end surfaces.

Weight: Basic specific gravity (ovendry weight/green volume) about 0.70; air-dry density 53 pcf.

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

Moisture content Bending strength Modulus of elasticity Maximum crushing strength

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

Green (67) 15,350 2,040 7,710

14% 20,670 2,170 10,050

Green (34) 11,400 2,060 5,300

12% 18,400 2,560 10,000

Janka side hardness 1,230 to 1,420 lb for green material and 1,480 to 1,640 lb for dry. Forest Products Laboratory toughness 430 in.-lb for green and 490 in.-lb for dry material (2-cm specimen).

Drying and Shrinkage: Rather difficult to season, dries slowly, liable to end splitting, warping is variable. Kiln schedule T8-B3 is suggested for 4/4 stock and T5-B1 for 8/4. Shrinkage green to ovendry: radial 6.2%; tangential 11.4%. Movement in service is rated as medium.

Working Properties: Rather difficult to machine because of high density, saws cleanly, dresses to a smooth finish, some tearing of interlocked grain, only moderate blunting of cutters, wood should be prebored for nailing.

Durability: Heartwood durability very variable and should be classified as nondurable. Sapwood is very susceptible to attack by powder-post beetle.

Preservation: Heartwood is extremely resistant to preservative treatments; sapwood classified as permeable.

Uses: Heavy construction, framing of boats, parquet flooring, heavy-duty flooring, utility furniture.

Additional Reading: (9), (34), (67)

M 150 282-3Logs are delivered to a sawmill in southern Nigeria. African mahogany

(mostly Khaya ivorensis) is in high demand on overseas markets. Export of logs fro

this region, as well as from most other tropical areas, is being restricted.

M 150 282-2Band mills in Ghana are designed to handle logs 5 feet and more in

diameter. Obeche or Wawa (Triplochiton scleroxylon) logs yield lumber favored for

joinery and millwork.

M 150 273-14In many areas of the tropics, fast-growing species are being introduced

future supplies of fuel wood and industrial wood. Batai (Albizia falcataria) is

a favored plantation species in the Philipines.

M 150 273-13 Shores spp. is still the major timber group harvested in Southeast

Asia. With modern chain saws, fellers no longer need scaffolding to get above larg

buttresses.