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| Name | keruing |
| Other Names | Keroewing, kerup, keruing, lagan, tampudau (Indonesia, Malaysia), yang, gurjun, in, eng, engurgun, kanyin, hollong (Burma), chloeuteal, khlong, thbeng, trach (Cambodia), gurjan (India), apitong (the Philippines), hora (Sri Lanka), dau, tro (Vietnam), eng, phluang, hieng (Thailand). |
| Botanical Name | Dipterocarpus spec. div.. |
| Family | Dipterocarpaceae. |
| Origin | Southeast Asia. |
| Tree Description | Heights vary from 30 to 60 m across each variety. Trunks measuring between 15 and 25 m in length are straight and cylindrical with diameters between 0.9 and 1.8 m, often with a long root buttress. |
| Available As | Planed timber |
| Wood Description | Keruing group woods vary in colour from greyish brown, light reddish brown, dark reddish brown to brown. Dry sapwood is clearly distinguishable from heartwood, is greyish while to brown in colour and is between 30 and 120 mm in width. Freshly cut or sawn surfaces have a characteristic resinous or spicy odour. Resin seeping from end grain can cause problems during processing. |
| Wood Type | Hardwood |
| Grain | Straight, sometimes shallow interlocked grain. |
| Texture | Moderately coarse to coarse. |
| Density | (580)/740/870/(1020) kg/m3 at 12% humidity, 1000 to 1050 kg/m3 when green. Densities and other properties can vary greatly due to the large number of Dipterocarpus varieties available as keruing. |
| Working | Moderate to major. |
| Drying | Very slow. Keruing is difficult to dry either in air or artificially. Major shrinkage, as well as susceptibility to bending and twisting in primarily plain-sawn and non-linear grained wood. Copius resin seepage can also cause problems. Remains stable if expertly dried. |
| Workability | Moisture, resin and silicon (< 0.5%) content play a major role when processing the wood. High resin content causes tools to stick and silicon blunts cutting tools. Whenever keruing is used where fitting is important, then it must be dried sufficiently prior to use. |
| Fixings and Fasteners | Good. |
| Bonding | Moderate, depending on constituent quantities |
| Pliability | Very poor. |
| Surface Finishing | Surface finishing is not particularly long-lasting for outdoor applications. Surface finish durability can be improved by treating the wood with a cellulose-based lacquer solution or acetone followed by pore filler. A thin preparation layer should be reapplied over the pore filler before applying the varnish system. |
| Durability | Moulds 3v. Termites G. |
| Strength Class | - |
| Impregnability | Heartwood 3v. Sapwood 2. |
| Peculiarities | The names listed above are all used for varieties of Dipterocarpus depending on the country of origin. It is difficult to distinguish between the varieties, although quality, weight and colour differences exist, as do levels of oily resins. Working with keruing can cause skin infections, nausea and infected splinter wounds. |
| Applications | Beams, posts and planks for heavy-duty construction work such as bridges, jetties, harbour projects, wagon and industrial flooring, parquet and strip flooring, pallets, ship hatches and staging. Low-density keruing trunks are stripped for triplex manufacture. |
| Quality Requirements | - |
Source: Houtvademecum, 8e druk 2001