3518

5(1): Timber trees; Major commercial timbers

Gonystylus Teijsm. & Binnend.

Bot. Zeitung (Berlin) 20: 265 (1862).

THYMELAEACEAE

x = unknown

Trade groups Ramin: lightweight to medium-weight hardwood, e.g. Gonystylus affinis Radlk., Gonystylus bancanus (Miq.) Kurz, Gonystylus forbesii Gilg, Gonystylus macrophyllus (Miq.) Airy Shaw, Gonystylus maingayi Hook.f., Gonystylus velutinus Airy Shaw.

Ramin. Indonesia: gaharu buaya (Sumatra, Kalimantan), medang keladi (Kalimantan). Malaysia: melawis (Peninsular), gaharu buaya (Sarawak). Philippines: lanutan-bagyo, anauan (general).

At present Gonystylus consists of about 30 species but this number will probably increase further because new species are regularly discovered. The species are distributed almost throughout the Malesian area with the exception of Central and East Java and the Lesser Sunda Islands. Eastward the distribution area extends towards the Solomon Islands, Nicobar and Fiji. The vast majority of species is found on Borneo (27), especially in Sarawak. Peninsular Malaysia and Sumatra come second with 7 species each, and the Philippines possess 2 species. All other areas are occupied by a single species. The most widespread one is Gonystylus macrophyllus.

The whitish timber of ramin is highly prized and popular as a decorative cabinet timber. More generally it is also suitable for furniture, interior decoration such as wall panelling, light flooring, toys, turnery, broom handles and other non-impact handles, Venetian blind slats, dowels, rulers, picture frames and drawing boards. Ramin is used for general light construction such as door and window frames, mouldings, skirtings, ceilings, partitions, stair treads and counter tops. Various other applications are planks, barrels, boxes and shipboards. Being highly susceptible to various attacks, the timber should always be used under cover. Ramin is very suitable for veneer, plywood and blockboard manufacture and can be made into a satisfactory quality of particle board.
The resin impregnated pathological heartwood of several species is well known as 'gaharu' or 'kayu garu' and is used as incense (just like Aquilaria spp.). The pounded fruits are sometimes used as a fish poison. A decoction of the roots of several species is administered after childbirth as a protective medicine.

Ramin is one of the major export timbers of South-East Asia. Indonesia is the most important exporter, followed by Sarawak and Peninsular Malaysia.
In 1983 the total volume of standing timber of ramin in Indonesia was estimated at 220 million m³; trees over 50 cm diameter comprise 89 million m³. The average production of ramin in Indonesia in 1991-1992 was 900 000 m³/year. Major production areas are central and southern Sumatra, Riau, West Kalimantan and, particularly, Central Kalimantan (average annual production 550 000 m³ in 1991-1992). In the early 1980s ramin was the most important species in Indonesia for sawnwood exports, accounting for 38% in volume and 46% in value. The average annual export was 598 000 m³ with a value of US$ 119 million. In 1987 the export of sawn ramin was 299 000 m³ (with a value of US$ 86 million) and in 1988 224 000 m³ (with a value of US$ 74 million). On June 13, 1991 the export tax on ramin timber in Indonesia was increased from US$ 500/m³ to US$ 1200/m³.
The average log production in Sarawak was 509 000 m³/year in the period 1981-1990; it was fairly constant over this period. Logging activities in Sarawak focus on ramin as one of the main timbers. In 1987, ramin accounted for 87% of the total sawn timber export from Sarawak. The export was 154 000 m³ in 1987, and 175 000 m³ in 1988. Logging activities in Sarawak are increasingly moving into hill dipterocarp forests, and supplies of ramin are expected to decline in future, once the virgin peat-swamp forests have all been logged for the first time. Sabah exports small amounts of sawn ramin timber; in 1992 exports amounted to 600 m³ with a value of US$ 250 000.
The average production of ramin logs in Peninsular Malaysia in the period 1982-1990 was 37 000 m³/year. The export of sawn ramin was 15 000 m³ (worth US$ 2.3 million) in 1983, and decreased to 7000 m³ (worth US$ 1.2 million) in 1986. In the period 1987-1990 the export was 14 000-15 000 m³/year (worth US$ 3.7-4.3 million), but in 1991 there was a sudden increase to 25 000 m³ (worth US$ 8.4 million). In 1992 it was 10 000 m³ with a value of US$ 3.9 million.
European countries are the major importers of ramin from Sarawak, in order of importance: Italy, Britain, the Netherlands, Germany, Belgium and Spain. Japan is also an important importer, mainly from Indonesia.

Ramin is a lightweight to moderately heavy hardwood. The heartwood is white to yellowish-white or yellow, sometimes weathering to straw-coloured, and not distinctly demarcated from the 3-6 cm thick sapwood. The density is 460-840 kg/m³ at 15% moisture content. The grain is straight or shallowly interlocked, texture moderately fine to moderately coarse and even. The wood surface is slightly lustrous and lacks a conspicuous figure.
At 15% moisture content, the modulus of rupture is 84-105 N/mm², modulus of elasticity 13 600-16 300 N/mm², compression parallel to grain 47-58 N/mm², shear 6-10.5 N/mm², cleavage 34-50 N/mm radial and 44-58 N/mm tangential, and Janka side hardness 2970-5800 N.
The rates of shrinkage are moderately high, from green to 15% moisture content 1.3-2.6% radial and 3.7-5.2% tangential, and from green to oven dry about 4.4% radial and 9.6% tangential. Ramin dries fast, but it is slightly susceptible to end splitting, cupping and warping. The use of an end coating can minimize end splitting. The timber should be dipped in a preservative solution after sawing as it is prone to powder-post beetle attack and blue stain which may cause considerable discoloration. Air seasoning of 4 cm thick boards takes about 70 days. In Malaysia kiln-drying schedule C is advised, but kiln schedule B for boards thicker than 4 cm. Kiln drying of 2.5 cm thick boards to 12% moisture content takes approximately 7 days. Kiln-dried boards are usually free from serious defects, but cupping may occur, particularly in tangential boards.
Ramin is easy to work with hand tools as well as machines. It is easy to saw and plane in both green and dry condition. It can easily be worked into smooth mouldings. Turning gives quite good results, but boring produces rough surfaces. Mortising, shaping and sanding give good results. Ramin is prone to splitting when nailed, so that pre-boring is recommended. The wood can be stained and polished well, and glued with all types of glue. Good veneer can be produced at a peeling angle of 92°30' without pretreatment, but mild soaking in hot water renders peeling easier. The veneer should be handled with care as there is a tendency towards tearing along the grain. It dries well without serious defects. Gluing with urea-formaldehyde makes good plywood. Ramin is suitable for making hardboard, but the boards show a fairly high water absorption.
Ramin is non-durable. Graveyard tests with stakes showed an average life in contact with the ground under tropical conditions of only 6 months, and a maximum life of 1-2 years. The wood is susceptible to blue stain and ambrosia beetle attack, and the resistance to dry-wood termites and wood-rotting fungi is poor. Ramin is, however, easy to treat with preservatives. The inner bark contains numerous fine brittle fibres which may cause skin and eye irritation, and wood dust has been reported to cause occupational asthma. Fresh wood has an unpleasant smell.
Ramin wood contains 62% cellulose, 29.5% lignin, 19% pentosan, 0.5% ash and no silica. The solubility is 6.1% in alcohol-benzene, 1.1% in cold water, 3.4% in hot water and 11.5% in a 1% NaOH solution. The energy value is 19 480 kJ/kg.

Small to medium-sized trees, up to 42 m tall, occasionally shrubs; bole cylindrical, straight, branchless for up to 21 m and up to 60(-120) cm in diameter, buttresses are thick if present, sometimes fluted at base; bark surface smooth to cracked, shallowly fissured or scaly, dull grey to red-brown or dark brown, occasionally with white patches, inner bark yellow, brown, pink or orange, laminated or fibrous, with glistening slightly irritating fibres on the cut surface; twigs striate, black or chocolate brown, pendulous, sometimes puberulous-velutinous when young but glabrescent. Leaves alternate, simple and entire, papery to thick-leathery, often sparsely hirsute below, especially on the midrib; petiole short, glabrous to velutinous, pellucid-punctate; stipules absent. Inflorescence usually terminal, paniculate, few-branched with short lateral branches; bracts minute, very early caducous. Flowers bisexual, actinomorphic, long-pedicelled; calyx more or less cupular, divided to about 1/4-1/3 in 5 petaloid thick tough lobes, densely setulose-hairy inside; corolla consisting of a ring of 7-40 small, more or less rudimentary petals, often shortly united at base; stamens about equal in number to the petals, rarely twice as many, anthers basifixed on short filaments and folded backwards; ovary sessile, globose, densely hispid-setulose, (2-)3-4(-8)-locular, style filiform, glabrous or pubescent, wiry, sinuate-contorted, stigma punctiform to capitate. Fruit a globose, or rarely lanceolate, woody, 2-5-valved and dehiscent capsule, 1-5-seeded. Seed large, up to 4 cm long, with a smooth softly coriaceous testa, partly enclosed in a thin aril, with thick horny cotyledons and lacking endosperm. Seedling with hypogeal germination, with a taproot emerging from one pole of the seed, the hypocotyl rupturing the testa and the shoot emerging through the slit; leaves arranged spirally, lower ones sometimes subopposite.

- Macroscopic characters:
Heartwood white to light yellowish-white, not distinct from the sapwood. Grain straight to shallowly interlocked. Texture moderately fine and even. Growth rings indistinct.
- Microscopic characters:
Growth rings indistinct. Vessels diffuse, usually 3-9/mm², solitary and in radial multiples of 2-3(-4), 110-190 µm in tangential diameter; perforations simple; intervessel pits alternate, round, 3-4 µm, apertures often coalescent; vessel-ray and vessel-parenchyma pits almost similar to intervessel pits; yellowish contents often present in perforation plate area. Fibres with distinct radial alignment, 1.2-1.9 mm long, thin-walled (wall 4-5 µm thick), with small, more or less distinctly bordered pits confined to the radial walls. Parenchyma paratracheal, winged-aliform to confluent, wings usually thin and long. Rays 9-11/mm, uniseriate, sometimes accompanied by biseriate rays or with frequent presence of biseriates (Gonystylus macrophyllus), 240-440 µm high, sometimes up to 2000 µm, homocellular (Kribs type homogeneous). Prismatic crystals and small styloids present; sometimes more than one crystal of various sizes in one cell of axial or ray parenchyma; crystals sporadic in some specimens.
Species studied: Gonystylus bancanus, Gonystylus macrophyllus.

Seedlings used for enrichment planting in Kalimantan showed an average growth in height of 12.5 cm/year. A mean annual diameter increment of young trees of 0.5-0.7 cm can be expected, attaining 1 cm under optimal conditions. Although seedlings can withstand a certain level of shade and competition, best growth is reported under light shade conditions and low density of weeds.
Flowering and fruiting of Gonystylus bancanus trees are at comparatively short but irregular intervals. In West Kalimantan the flowering time is August - October. Fruits ripen in about 2 months after flowering. In Sulawesi it has been demonstrated that seeds of Gonystylus macrophyllus are dispersed by the bat Rousettus celebensis; the fairly large seeds probably cannot be easily carried by the bats and may frequently be dropped.

The genus Gonystylus is treated here as a member of the family Thymelaeaceae. Together with the related small genera Aetoxylon and Amyxa, Gonystylus comprises a distinct subfamily (Gonystyloideae) within the Thymelaeaceae. This subfamily has sometimes been given the rank of family (Gonystylaceae); some authors place it next to the Thymelaeaceae, others regard it as more related to Tiliaceae or Flacourtiaceae. In dry condition the characteristic colours of the foliage can be used for species identification. The identification of saplings is often difficult because of the differences in habit of young and mature plants. The absence of resin canals precludes confusion with any dipterocarp timber.

The species of ramin are typically found in primary, non-inundated rain forest at low and medium elevations, reaching 1200 m altitude in Sumatra and 1500 m in Borneo and the Philippines. The ecology of the most important species Gonystylus bancanus differs, however, from most of the others. In Sarawak and Brunei it is an important, often gregarious component of the mainly coastal peat-swamp forest, where it occurs in both the peripheral mixed swamp forest and also in alan (Shorea albida Sym.) forest and 'padang paya' forest (pole-sized peat-swamp forest). It is also found in heath forest. In mixed swamp forest Gonystylus bancanus is often the most abundant large tree with up to 20 trees/ha with a diameter above 50 cm and is locally the single dominant species. It is principally associated with several Shorea species, Copaifera palustris (Sym.) de Wit and Dactylocladus stenostachys Oliver (jongkong). The latter may in some places be more abundant than Gonystylus bancanus. Other associates encountered are: Dyera lowii Hook.f. (jelutong), Palaquium spp. (nyatoh), Cratoxylum arborescens (Vahl) Blume (geronggang), Agathis borneensis Warb. (kauri), Durio spp. (durian), Dipterocarpus spp. (keruing) and Dryobalanops spp. (kapur). In alan swamp forest Gonystylus bancanus is much less abundant and usually occurs unevenly. It seems to prefer the fringes of this forest type and trees rarely exceed 85 cm in diameter. In the 'padang paya' forest Gonystylus bancanus is fairly common but rarely exceeds a diameter of 50 cm. In a few heath forests on podzol Gonystylus bancanus is often found in association with Calophyllum spp. (bintangor) and its diameter is usually less than 75 cm. Gonystylus bancanus prefers flat land without influence of tidal water and an acid, rather poorly drained soil. It is an evergreen tree, and young plants require shade, whereas moderately large trees will flourish in full sunlight. In Indonesia species of ramin grow on red-yellow podzolic soil, peat soil, alluvial soil and podzol at sea-level. Gonystylus maingayi is somewhat exceptional, growing on lithosol on steep hills up to 200 m altitude.

Ramin (Gonystylus bancanus) can be planted using wildlings, nursery-raised seedlings and cuttings. In experiments with enrichment planting, nursery-raised seedlings showed good survival (67%) and height increment (12.4 cm/year) when compared with cuttings (44% and 5.5 cm/year, respectively) and wildlings (40% and 12.6 cm/year, respectively). Since seedlings and saplings require shade, the planting should be in the strip or line planting system in logged-over or secondary peat-swamp forest, with a spacing of 5 m 5 m in logged-over forest and 3 m 1 m in secondary forest. After 2-3 years the shade can be gradually removed to stimulate growth.

In Indonesia, natural ramin peat-swamp forest is managed under the Indonesian selective felling and planting system, with a diameter limit of 35 cm and a cutting cycle of 35 years. At least 25 healthy trees/ha of over 15 cm diameter should be left as core trees. In planted ramin forest, the first thinning can be carried out at an age of 5 years, and from then on at intervals of 3 years up to the age of 20 years, and subsequently at intervals of 5 years up to the felling age.
In Sarawak large areas of logged-over mixed peat-swamp forest are regularly treated to stimulate regeneration and growth of ramin. The problem is that ramin is shade-loving and grows slower than other species in a regenerating forest.

Access to the swamp forest where ramin grows is often very difficult because of the spongy soil, stagnating water and the presence of fallen branches and trees. In Kalimantan woodslide tracks are laid out towards each felled tree so that personnel work out of the water. The trees are mostly harvested by hand but chain saws are used for felling and cross cutting and an engine pulls small trucks to the floating woodyard. Log beds and sleepers support the line on which rail is fixed for transport of logs above the water level (usually the water is 10-50 cm deep). Logs are hauled on wood sleds by manpower.
In depots the logs are sprayed with preservatives. This is necessary, as they are very susceptible to blue stain and insect attack. In Sarawak a mixture of benzene hexachloride, sodium pentachlorphenate, borax and water (5:1:2:10) is used for dipping, in West Kalimantan agrocide (1/3 kg/m³), borax (1/3 kg/m³) and sodium pentachlorphenyl (2 kg/m³).
The logs are transported by river. Ramin rafts are formed by lashing together logs of similar length (about 4 m), laid at right angles to the current; each unit consists of 200-300 logs, i.e. 150-250 m³ volume. The logs are lashed together by rattan straps, and the rafts by nylon cables.

In Indonesia, the productive ramin peat-swamp forest of West Kalimantan has an extent of 1 million ha with an average standing stock of 30 m³/ha. In Central Kalimantan the ramin forest covers about 1.5 million ha with an average standing timber volume of 25 m³/ha. The annual allowable cut was determined at 696 000 m³/year for West Kalimantan with a potential of 480 000 m³/year, and at 865 000 m³/year with a potential of 600 000 m³/year for Central Kalimantan. Merchantable logs of ramin constitute about 3 m³ of timber.
In Sarawak the number of ramin trees over 20 cm in diameter is estimated at 2-20 trees/ha in mixed swamp forest. The standing stock of ramin may be as high as 35 m³/ha in mixed peat-swamp forest and 17 m³/ha in alan swamp forest.

Gonystylus bancanus occurs widely and is often dominant. The potential of swamp forest in Kalimantan, for instance, is 40-60 m³/ha of timber, of which ramin constitutes 27-40 m³/ha and other common timbers such as kauri (Agathis spp.), meranti (Shorea spp.) and keruing (Dipterocarpus spp.) only 1-3 m³/ha each. Stands of Gonystylus bancanus, as the main source of ramin timber, have been heavily depleted. The species is vulnerable because of heavy exploitation and habitat loss. In Sarawak, where large stands occur, it has been heavily overcut for some decades, and in Kalimantan the pressure on natural populations is also very high. In Peninsular Malaysia large areas of peat-swamp forest have been cleared for agriculture, especially to establish oil-palm and pineapple plantations.
The large-scale exploitation of ramin is followed by replanting or promoting activities for natural regeneration only in Sarawak. The great majority of the populations of Gonystylus bancanus are outside nature reserves and lack protection. However, the species is not currently threatened with extinction as it also occurs on sites where commercial exploitation is not profitable, and in Sarawak natural regeneration is stimulated. Other Gonystylus species are often confined to a more restricted area and occur more scattered; they are probably more easily liable to genetic erosion when forests are converted into agricultural land.
At the beginning of 1992 ramin was proposed for inclusion in the CITES Appendix II, which would strictly regulate trade in order to avoid over-exploitation. Indonesia and Malaysia successfully protested against this proposal, arguing that the stable production figures show that it is not yet rare or threatened.

In order to halt the over exploitation of natural ramin forest, the amount of harvested and traded timber should be restricted. Logged-over forest should be regenerated by means of enrichment planting, and large areas of swamp forest should be designated as protected reserves. Information on silviculture of ramin is available from Sarawak only, and more research is badly needed. Some timbers are good substitutes for ramin, e.g. perupok (Lophopetalum spp.) which is particularly harvested in East Kalimantan. Rubberwood (Hevea brasiliensis (Willd. ex A.L. Juss.) Muell. Arg.) seems to be a promising substitute, as it can be planted easily, grows rapidly and has fairly similar wood properties; it is already planted on a large scale for the production of timber.

Airy Shaw, H.K., 1953. Thymelaeaceae - Gonystyloideae. In: van Steenis, C.G.G.J. (Editor): Flora Malesiana. Ser. 1, Vol. 4. Noordhoff-Kolff, Djakarta. pp. 349-365.
Browne, F.G., 1955. Forest trees of Sarawak and Brunei and their products. Government Printing Office, Kuching. pp. 337-343.
Burgess, P.F., 1966. Timbers of Sabah. Sabah Forest Records No 6. Forest Department, Sabah, Sandakan. pp. 298-306.
IUCN Species Survival Commission Trade Specialist Group, 1992. Inclusion of Gonystylus bancanus in Appendix II. Analyses of proposals to amend the CITES Appendices. IUCN - the World Conservation Union. pp. 199-200.
Laurent, D., 1986. Kalimantan ramin and agathis, where do you come from and how are you harvested? Revue Bois et Forêts des Tropiques 211: 75-88.
Martawijaya, A., 1973. Sifat dan kegunaan kayu ramin [Properties and uses of ramin]. Laporan No 4. Lembaga Penelitian Hasil Hutan, Bogor. 29 pp.
Martawijaya, A., Kartasujana, I., Kadir, K. & Prawira, S.A., 1986. Indonesian wood atlas. Vol. 1. Forest Products Research and Development Centre, Bogor. pp. 119-124.
Sim, H.C., 1983. Malaysian timbers - ramin. Malaysian Forest Service Trade Leaflet No 74. Malaysian Timber Industry Board, Kuala Lumpur. 7 pp.
Soerianegara, I. & Alrasjid, H., 1978. Percobaan (enrichment planting) pohon ramin (Gonystylus bancanus Kurz) pada areal bekas penebangan di Komplek Hutan Teluk belanga, Kalimantan Barat [Trial enrichment planting of ramin (Gonystylus bancanus Kurz) in the Teluk belanga forest complex, West Kalimantan]. Laporan No 269. Lembaga Penelitian Hutan, Bogor. 14 pp.
Wiroatmodjo, P., 1975. Ramin (Gonystylus spp.) forest in Kalimantan. Kehutanan Indonesia 2: 868-892.

I. Soerianegara (general part), E.N. Sambas (general part), A. Martawijaya (properties), S. Sudo (wood anatomy), L.E. Groen (selection of species)

Gonystylus affinis
Gonystylus bancanus
Gonystylus brunnescens
Gonystylus confusus
Gonystylus consanguineus
Gonystylus forbesii
Gonystylus keithii
Gonystylus lucidulus
Gonystylus macrophyllus
Gonystylus maingayi
Gonystylus velutinus
Gonystylus xylocarpus

Soerianegara, I., Sambas, E.N., Martawijaya, A., Sudo, S. & Groen, L.E., 1993. Gonystylus Teijsm. & Binnend.. In: Soerianegara, I. and Lemmens, R.H.M.J. (Editors): Plant Resources of South-East Asia No 5(1): Timber trees; Major commercial timbers. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea

The following species in this genus are important in this commodity group and are treated separatedly in this database:
Gonystylus affinis
Gonystylus bancanus
Gonystylus brunnescens
Gonystylus confusus
Gonystylus consanguineus
Gonystylus forbesii
Gonystylus keithii
Gonystylus lucidulus
Gonystylus macrophyllus
Gonystylus maingayi
Gonystylus velutinus
Gonystylus xylocarpus