Properties and Uses

Resak

The Standard Malaysian Name for the timber of Cotylelobium spp. and Vatica spp. (Dipterocarpaceae). The timber is a heavy hardwood with a density of 655–1155 kg m^–3air dry. The sapwood is lighter in colour than the heartwood and is sharply defined in Cotylelobium but not generally so in Vatica. The heartwood is pale yellow when fresh and turns to deep red-brown on exposure in Cotylelobium and a fine brown with a green tinge in Vatica. Texture is fine and even, with straight or only shallowly interlocked grain. The timber is strong (Strength group B). It is difficult to resaw and cross-cut in Vatica, while Cotylelobium is moderately easy to slightly difficult to resaw. Planing is easy to slightly difficult and the finished surface is smooth. The timber seasons fairly slowly with very negligible degrade. Only slight cupping, end-checking, splitting and surface-checking are noted during drying. 13 mm boards take approximate 3 months to air dry, while 38 mm boards take 5 months. Shrinkage is high, especially in the tangential direction. Radial shrinkage averages 1.5% while tangential shrinkage averages 3.4%. The timber is very durable and is very difficult to treat.

USES: The timber is suitable for all forms of heavy construction, bridges, piling, beams, posts, joists, heavy duty flooring, power transmission poles, railway sleepers, parquet flooring, heavy duty furniture and wooden containers.

Vernacular names applied include resak (P.M., Sab. and Sar.) with various epithets, balau (P.M.) in error, damar keluang (Ph.), jenuong (Jh.) and keruing babi (P.M.). Major species include Cotylelobium lanceolatum, C. melanoxylon; Vatica bella, V. cuspidata, V. flavida, V. havilandii, V. heteroptera, V. lowii, V. maingayi, V. mangachapoi, V. nitens and V. scortechinii.