Eusideroxylon zwageri

Belian

Borneo ironwood

Family: Lauraceae

Other Common Names: Tambulian (Philippines), Onglen, Un (Indonesia).

Distribution: Throughout the lowlands of Sabah extending into the remainder of Borneo, other Indonesian islands, and the Philippines; occasionally abundant.

The Tree: May reach a height of 100 ft, with trunk diameters of exploitable trees up to 36 in.

The Wood:

General Characteristics: Heartwood light brown to almost bright yellow when freshly cut, darkens on exposure to a deep reddish brown, very dark brown, or almost black; sapwood bright yellow, darkening on exposure, sharply defined. Texture fine and even; grain straight or only slightly interlocked; somewhat lustrous; has a lemon-like odor that persists, no marked taste.

Weight: Basic specific gravity (ovendry weight/green volume) 0.86 to 0.92; air- dry density 64 to 71 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 (71) 20,850 2,570 11,590

11% 25,810 2,650 13,620

Green (9) 19,500 2,620 11,570

Janka side hardness 2,845 lb for green material and 3,020 lb for dry.

Drying and Shrinkage: Reported to season easily with little degrade due to warping and checking. Kiln schedule T2-C2 is suggested for 4/4 stock and T2-C1 for 8/4. Shrinkage green to ovendry: radial 4.3%; tangential 7.5%.

Working Properties: In spite of its high density the wood can be sawn without difficulty, blunting of cutters is only moderate; machines cleanly; reported to be difficult to glue with the synthetic resins.

Durability: Heartwood is rated as very durable, service life of 50 to 100 years in ground contact is reported; immune to termite attack. A service life of 20 years and more for marine work in tropical waters is reported.

Preservation: Not treatable, but sapwood is responsive.

Uses: Heavy construction, marine work, boatbuilding, piling, printing blocks, specialty furniture, industrial flooring, roofing shingles, tool handles.

Additional Reading: (9), (11), (53), (71)

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.