The TreeThe trees are evergreen and generally large, depending on locality, reaching heights of 25m to 45m and a diameter of 0.75m to 1.5m with a straight, cylindrical bole often clear of branches to 21 m above a small buttressed base.
The TimberThe sapwood is greyish-brown and distinct, and usually 50mm to 75mm wide. The heartwood varies from light red to reddish-brown or brown, darkening on exposure. The grain is usually straight but may be shallowly interlocked, and the texture is moderately coarse or coarse, but even. The timber contains an oleo-resin which exudes in a number of pieces especially on the end grain. The various species vary in weight from 640 kg/m3 to 960 kg/m3 but an average for the group is about 740 kg/m3 when dried.
DryingThe timbers of this group dry slowly, and it is difficult to achieve uniform drying particularly in thick stock or in quarter-sawn material. High temperatures aggravate the exudation of resin, and care is therefore needed in order to reduce this to a minimum and also to reduce the tendency for cupping to occur. There is high shrinkage during drying, and a corresponding high movement potential.
StrengthKeruing generally compares with teak in most strength categories, but it is a little stiffer, and about 40 per cent more resistant to shock loads.
Working QualitiesDifficult - The variations that exist between the different species and within species in respect of resin content, type of grain and hardness, affect the general ease of working, dulling of cutters and finishing properties. The timbers vary from hard to very hard and horny in cutting across the grain, and whereas straight grained material is capable of clean, slightly fibrous finish in planing and moulding, quarter-sawn, or interlocked-grained material picks up during these operations unless cutting angles are reduced to 200. The wood stains satisfactorily, but due to the resin, varnishing and polishing require a lot of care. It takes nails and screws reasonably well, but its gluing properties are variable.
Latin NameDipterocarpus spp, Dipterocarpus cornutus, Dipterocarpus costulatus, Dipterocarpus crinitus, Dipterocarpus sublamellatus, Dipterocarpus apterus, Dipterocarpus lowii, Dipterocarpus verrucosus, Dipterocarpus gracilis, Dipterocarpus acutangulus, Dipterocarpus grandiflorus, Dipterocarpus warburgii
Also known asApitong, Sabah gurjun, yang, Malaysian keruing, Indonesian keruing, Sarawak keruing, kruen
OriginSouth East Asia, Burma, India, The Andamans, Sri Lanka, Thailand, South Vietnam, Cambodia, the Philippines