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Keruing
(Dipterocarpaceae)
Tree description and natural occurrence
Keruing is produced by 70 or so species of the genus
Dipterocarpus. They are large hardwoods, some species
attaining a height of 70 metres. |
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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.
Strength Group.
S3
unseasoned, SD3 seasoned.
Stress Grades.
F8,
F11, F14, F17 (unseasoned), F14, F17, F22, F27 (seasoned), when
visually stress graded in accordance with AS2082-2000, ‘Visually
stress-graded hardwood for structural purposes.’
Shrinkage to 12% MC.
Shrinkage varies between species but averages approximately 7.0 %
(tangential); 3.5 % (radial).
Unit Shrinkage.
Not
available.
Durability.
Class 4
– Suitable for use only in continuously dry situations under cover,
well ventilated, clear of the ground and fully protected from the
weather and other dampness.
Lyctid Susceptibility.
Untreated sapwood susceptible to lyctid borer attack.
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.
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