Scientific name
Dipterocarpus species (combined group of about 70 species). Family: Dipterocarpaceae
Local names
Apitong, hagokhak, panau (Philippines), dan (vietnam), yang, eng (Thailand), kerunwing, kruen, kurjun, Klalar, lagan (Indonesia), bagac.
Description and natural occurrence
Keruing is the name given to timber from 70 or so species of the genus Dipterocarpus. They are large hardwoods, some species attaining a height of 70 m.
Keruing occurs throughout Indonesia, Malaysia, Philippines, Sabah, Sarawak, Brunei, Pakistan, India, Burma, Borneo, Thailand, Sri Lanka and Kampuchea.
Wood appearance
Colour. Heartwood varies between species but is most commonly red-brown. Variations include deep-pink, orange-pink, purple-red. Sapwood is usually lighter in shade and may have yellow or greyish tinges. Wood darkens with age.
Grain. Grain is generally straight but may be slightly interlocked resulting in some stripe figure on the radial surface. Texture varies between species and area of origin from fine to coarse but even.
Wood properties
Density. 790 kg/m3 at 12% moisture content; approximately 1.3 m3 of seasoned sawn timber per tonne.
Lyctine susceptibility. Untreated sapwood susceptible to lyctine borer attack.
Termite resistance. Not resistant.
Preservation. Keruing is moderately resistant to impregnation with preservatives, resulting in a possibility of uneven distribution of preservative.
Seasoning. Difficult to season without degrade causing checks, splits and warping. Pre-steaming before drying can reduce degrade.
Hardness. Moderately hard (rated 3 on a 6 class scale) in relation to indentation and ease of working with hand tools.
Machining. The presence of silica and resin can make machining difficult. Cutting edges must be kept sharp, and tungsten-tipped tools give best results.
Fixing. Nails satisfactorily; stock may stain with iron fastenings.
Gluing. Gluing qualities variable.
Finishing. Stock with high resin content has a poor base for all finish coatings. Less resinous stock finishes satisfactorily.
Uses
Construction. Laboratory flooring (has good acid resistance) internal flooring, protected framing and boards.
Decorative. Internal joinery and mouldings, lining, panelling.
Others. Framework of carriages and wagons.
Identification features
Sapwood. Grey-brown, distinct from heartwood.
Heartwood. Red brown to dark brown.
Texture. Moderately coarse, uniform, straight grain.
Vessels. Predominantly solitary, large, visible to the naked eye, uniform diffuse distribution. Heavily tylosed in some species, but not in others.
Parenchyma. Apotracheal and paratracheal; apotracheal as scattered or confluent patches containing vertical resin canals; paratracheal very sparse as borders to vessels, often distinct.
Rays. Of two distinct sizes; medium and small. Medium size visible to the naked eye, quite prominent on radial surfaces.
