Derum


INTRODUCTION

The Standard Malaysian Name as well as the ASEAN Standard Name for the heavy timbers of Cratoxylum spp. (Guttiferae). Vernacular names applied include derum (Peninsular Malaysia) with various epithets, belunchus (Peninsular Malaysia), dat tetong (Sarawak), entemu (Sarawak), geronggang (Peninsular Malaysia and Sabah) with various epithets, melan (Sarawak), mirinos (Sarawak), nyalin bahe (Sarawak), patok tilan (Sarawak), raja tugag (Sarawak), selangan biabas (Sabah), serungan (Sabah), serungan batu (Sabah) and sidodot (Sarawak). Major species include C. cochinchinense, C. formosum and C. maingayi. The sapwood is not differentiated from the heartwood, which is brown to red-brown with a purple tinge.

Also known as Batun, Gerunggung and Mampat (Indonesia); Geronggang (Brunei); Leuang, Tiou-tiou and Tiu som (Laos); Bebya (Myanmar); Guyong-guyong, Paguringon and Salinggogon (Philippines); and Tiu-khao and Tiu-kliang (Thailand).


DENSITY

The timber is moderately hard to hard and moderately heavy to heavy. It has been classified under Medium Hardwood with a density of 705-945 kg/m3 air dry.


NATURAL DURABILITY

The timber is moderately durable.


TEXTURE

Texture is fine and even, with straight or interlocked grain.


STRENGTH PROPERTIES

The timber falls into Strength Group B (Burgess, 1958) or SG 4 (MS 544:Part 2:2001).


MACHINING PROPERTIES

It is slightly difficult to difficult to resaw and easy to difficult to cross-cut. Planing is easy to fairly easy and the planed surface is smooth.


AIR DRYING

The timber seasons fairly slowly without any defects at all. 13 mm thick boards take approximately 3 months to air dry, while 38 mm thick boards take 6 months.


SHRINKAGE

Shrinkage is very high, with radial shrinkage averaging 2.3% and tangential shrinkage averaging 4.6%.


USES

The timber is suitable for heavy and medium construction under cover, posts, telegraphic and power transmission posts and cross arms, tool handles (impact), pallets (expendable or permanent type), flooring, vehicle bodies (framework, floor boards and planking), plywood, door and window frames and sills, panelling, mouldings, partitioning, staircase (carriage, newel, riser, stringer, tread, bullnose, round end and winder), furniture, carving and ornamental items.


REFERENCES

  1. Burgess, H.J. 1958. Strength Grouping of Malaysian Timbers. Malayan Forest Service trade Leaflet No. 25. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 15 pp.
  2. Menon, P.K.B. 1986. Uses of Some Malaysian Timbers. Revised by Lim, S.C. Timber Trade Leaflet No. 31. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 48 pp.
  3. MS 544:Part 2:2001. Code of Practice for the Structural Use of Timber: Permissible Stress Design of Solid Timber.
  4. 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.