Properties and Uses

Balau

The Standard Malaysian Name for the heavy, yellow to brown timbers of the genus Shorea (Dipterocarpaceae). The timber is a heavy hardwood with a density of 850–1155 kg m^–3air dry. The sapwood is lighter in colour than and is sharply defined from the heartwood, which is yellow or grey-brown and darkens to deep brown on exposure. Texture is fine and even, with deeply interlocked grain. The timber is very strong (Strength group A). It is moderately easy to difficult to resaw and easy to difficult to cross-cut. Planing is easy to difficult and the planed surface is smooth to moderately smooth. Nailing property is rated very poor. The timber seasons very slowly, with severe end-checking and splitting, moderate surface-checking and staining as the main sources of defects. 13 mm boards take 4 months to air dry, while 38 mm boards take 8–10 months. Shrinkage is high, with radial shrinkage averaging 1.8% and tangential shrinkage averaging 3.7%. The durability of the timber varies from durable (S. glauca and S. laevis) to very durable (S. maxwelliana) and is extremely resistant to treatment with preservatives.

USES: The timber is suitable for all forms of heavy construction, bridges, wharves, railway sleepers, power-line poles, boat building, door and window frames, joists, beams, rafters, heavy duty flooring, parquet flooring and heavy duty furniture.

Vernacular names applied include balau (P.M.) with various epithets, selangan batu No. 1 (Sab.), selangan batu (Sab. and Sar.) and other localised names too numerous to be listed here. Major species include S. atrinervosa, S. foxworthyi, S. glauca, S. laevis, S. materialis, S. maxwelliana, S. submontana and S. sumatrana.