Bakau

INTRODUCTION

The Standard Malaysian Name for the timbers of Bruguiera spp., Ceriops spp. and Rhizophora spp. (Rhizophoraceae). Vernacular names applied include bakau (Peninsular Malaysia, Sabah and Sarawak) with various epithets, bangkita (Sabah), berus (Peninsular Malaysia), berus mata buaya (Peninsular Malaysia), beus (Sabah), langgadai (Sabah), lenggadai (Peninsular Malaysia and Sabah), mata buaya (Peninsular Malaysia and Sabah), putut (Sabah), tengar (Peninsular Malaysia), tumu (Peninsular Malaysia) with various epithets and berus (Peninsular Malaysia and Sarawak) with various epithets. Major species include Bruguiera cylindrica, B. gymnorrhiza, B. hainesii, B. parviflora; Ceriops tagal; Rhizophora apiculata and R. mucronata. The sapwood is in various shades of light yellow-brown, light brown, light red-brown or light pink-brown and is difficult to distinguish to moderately distinct from the heartwood, which is grey-brown, yellow-brown, red-brown or purple-brown and usually darkens on exposure and becomes more red.

Also known as Bakau (Brunei); Prasak (Cambodia); Lailai (Fiji); Bruguiera (India); Bakau, Tanjang and Tengar (Indonesia); Byu, Byu-chidauk, Byu-o-talon and Kabaing (Myanmar); Black Mangrove (Papua New Guinea); Bakauan, Bussain, Langarai, Pototan and Tangal (Philippines); Tongo (Samoa Islands); and Kong Kang, Prong, Prui and Rui (Thailand).


DENSITY

The timber is very hard and very heavy with a density of 630-1,170 kg/m3 air dry.


NATURAL DURABILITY

The durability of the timber varies with species, e.g. Rhizophora apiculata (bakau minyak), Bruguiera gymnorrhiza (tumu merah) and B. sexangula (tumu puteh) are classified as moderately durable whereas Bruguiera parviflora (lenggadai) is classified as non-durable.


TEXTURE

Texture is fine and even, with fairly straight and usually interlocked grain.


STRENGTH PROPERTIES

The timber falls into Strength Group A (Burgess, 1958).


MACHINING PROPERTIES

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


AIR DRYING

The timber is reported to be difficult to season, being liable to check and end-split.


SHRINKAGE

Shrinkage is very high especially in the tangential direction, with radial shrinkage averaging 1.4% and tangential shrinkage averaging 5.1%.


USES

The timber is suitable for handles of striking tools, temporary structures, scaffolding, piling, flooring (heavy traffic), firewood, charcoal, pulp and paper as well as rayon.


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. 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.