Tuai

INTRODUCTION

The Standard Malaysian Name as well as the ASEAN Standard Name for the timber of Bischofia javanica (Euphorbiaceae). Vernacular names applied include jitang (Peninsular Malaysia). This genus has only one species, viz. B. javanica. The sapwood is brick red-brown and is sharply defined from the heartwood, which is purple-red-brown and darkens on exposure.

Also known as Java cedar (Australia); Koka (Fiji); Bishopwood and Uriam (India); Bintungan, Gadog, Gintungan and Kerinjing (Indonesia); Khom fat (Laos); Uriam (Pakistan); Java cedar (Papua New Guinea); Tuai (Philippines); Pradu-som, Term and Toem (Thailand); and Nhoi (Vietnam).


DENSITY

The timber is moderately hard and moderately heavy with a density of 545-880 kg/m3 air dry.


NATURAL DURABILITY

The timber is non-durable.


PRESERVATIVE TREATMENT

The sapwood is amenable to preservative treatment while the heartwood is refractory.


TEXTURE

Texture is moderately fine to rather coarse but even, with interlocked grain.


MACHINING PROPERTIES

It is reported to be slightly difficult to work but planes to a smooth finish.


AIR DRYING

The timber is reputed to be very difficult to season without serious defects. Cracks, warping and even honeycombing have been noted during seasoning.


SHRINKAGE

Shrinkage is very high and may account for the seasoning problems of this timber. Work done in Australia indicated that radial shrinkage to be as high as 2.6% and tangential shrinkage to be 6.2% (green to 12% moisture content).


USES

The timber is not likely to be used extensively due to its adverse properties. The timber may be suitable for temporary planking, packing boxes and crates and charcoal manufacture.


REFERENCE

  1. Wong, T. M. 1982. A Dictionary of Malaysian Timbers. Revised by Lim, S. C. & Chung, R. C. K. Malayan Forest Records No. 30. Forest Research Institute Malaysia, Kuala Lumpur. 201 pp.