Campnosperma (PROSEA)

Plant Resources of South-East Asia
Introduction

Protologue: Hooker's Journ. Bot. Kew Gard. Misc. 6: 65 (1854).

Family: Anacardiaceae

Chromosome number: x= unknown

Trade groups

Terentang: lightweight timbers, Campnosperma auriculatum (Blume) Hook.f., C. brevipetiolatum Volkens, C. coriaceum (Jack) Hallier f. ex v. Steenis, C. montanum Lauterb. and C. squamatum Ridley.

Vernacular names

Terentang

oreywood, cedrol (En)
Indonesia: pauh lebi, tumbus (Sumatra)
Malaysia: kelinting, melumut, serentang
Papua New Guinea: campnosperma
Thailand: nangpron (peninsular), huasum (Trang), sangtrang (Nakhon Si Thammarat).

Origin and geographic distribution

Camnosperma, comprising about 10 species, is distributed over a very large area including South and Central America, Madagascar (1 species), the Seychelles (1 species), Sri Lanka, the whole of South-East Asia, Micronesia and Melanesia. In South-East Asia 5 species occur; Campnosperma species are found in Thailand (1 species), Peninsular Malaysia (3 species), Sumatra (2 species), Borneo (3 species), Sulawesi (1 species), the Moluccas (2 species) and New Guinea (3 species). Some species show a western Malesian area of distribution (C. auriculatum, C. squamatum), others occur in eastern Malesia (C. brevipetiolatum, C. montanum) or throughout Malesia (C. coriaceum). Campnosperma is absent from Java and the Lesser Sunda Islands, and also from the Philippines.

Uses

Terentang supplies a soft and lightweight timber useful for several purposes for which heavier timbers are unsuitable. It is not durable and thus suitable only for making short-lived items. Terentang timbers are commonly used for making matchboxes and splints; they are easily peeled to make veneer and can be easily folded. The timber is also used for making coffins, cigar and instrument boxes, blackboards, drawing boards, and drawers. In some sawmills the timber is converted into boards for packing crates and other low-grade uses. It provides raw material for the manufacture of chipboard and pulp. The timber is useful for light general purposes such as siding and sheathing, shelving, furniture, turnery and moulding. It can also be used for making artificial limbs and ladies' sandals. It is a substitute for jelutong (Dyera costulata (Miq.) Hook.f.) in pencil manufacture but is of inferior quality for this purpose. It is used in plywood manufacture as core material rather than as surface veneers, but in the Solomon Islands it is sometimes applied as fancy veneer. The wood is used commercially in Australia for TV cabinets, paint-grade face veneer and construction veneer in plywood. The timbers exported to Japan are mainly used for making drawers, alcove posts, laminated wood, plywood and packing cases. In Korea, the timbers are found to be suitable for cores of furniture and plywood, packing materials, pulp and particle board. The timber is locally used for making canoes.

It is reported that in Papua New Guinea an oil, called "tigaso oil", is extracted from the wood. This oil is rubbed on the skin as an antiparasiticum and it is used to alleviate harness sores on horses. It also serves as a body oil for decoration, and as a hair oil. The leaves are sometimes used to pack sago, meat and fish for cooking. The seeds of C. auriculatum contain oil which is extracted in Sumatra and used for culinary purposes and as lamp oil.

Production and international trade

In Peninsular Malaysia terentang timber is mostly used locally. Only a small volume of graded and ungraded terentang sawn timber was exported from 1980 to 1983, totalling about 475 m³. The export of terentang sawlogs from Peninsular Malaysia was banned in 1979 (exports of sawlogs of various commercial timbers were banned between 1972 and 1983). The log production in Peninsular Malaysia increased from 12 000 m³ in 1986 to about 25 000 m³ in 1989 by an average of 19 000 m³/year. In this period there was an increase in the consumption of terentang logs by plywood/veneer mills: about 6400 m³ in 1986 and 10 700 m³ in 1989. In 1992 9000 m³ of terentang logs was exported from Sabah with a value of US$ 600 000.

In Papua New Guinea the timber is ranked in MEP (Minimum Export Price) group 4 and fetched a minimum export price of about US$ 43/m³ for saw logs in 1992. Japan imports terentang timber from Sabah, Sarawak, New Guinea and sometimes in large quantities from the Solomon Islands.

Properties

Terentang is a lightweight and soft timber. The heartwood is pink when fresh, becoming grey-pink on exposure, and not distinctly differentiated from the sapwood. The density is (310-)350-500(-600) kg/m³ (average 435 kg/m³) at 15% moisture content. The grain is shallowly to deeply interlocked, texture very fine and even.

At 15% moisture content the modulus of rupture is 42-52 N/mm², modulus of elasticity 6500-9000 N/mm², compression parallel to grain 20-26 N/mm², compression perpendicular to grain 2-3 N/mm², shear 6-9 N/mm², cleavage 18-38 N/mm radial and 18-39 N/mm tangential, and Janka side hardness 1470-1540 N.

The rates of shrinkage of terentang are moderately high; from green to 15% moisture content 1.6-2.1% radial and 3.2-5.5% tangential. Terentang is somewhat liable to stain and should be seasoned as rapidly as possible in well ventilated sheds. Although the timber does not normally split and is not particularly liable to surface checking, stacks of thin boards must be weighted down to prevent splitting and bowing. The timber of C. auriculatum dries very fast. Green timber of 25 mm and 30 mm thick (average 85% moisture content) can be air dried in 1 and 2 months respectively. However, the timber of C. coriaceum dries much slower and 40 mm thick boards take about 5 months to air dry. Based on its low density and air drying properties, terentang timber can be kiln-dried using red meranti (Malaysian schedule F) or jelutong (schedule H) kiln drying schedules. Terentang shrinks slightly more than the other timbers with similar density such as jelutong (Dyera costulata), sesendok (Endospermum spp.) and pulai (Alstonia spp.).

Despite its lightness, the timber is not particularly easy to saw because of the fibrous nature of the wood and the presence of interlocked grain. It does not severely blunt sawteeth, but they become gummed up with a fine resinous sawdust. Surfaces normally become woolly. However, C. coriaceum and C. brevipetiolatum are described as easy to saw, cross cut and plane, although the quality of finish is rough to woolly. Suitable clearance and hook angles are required to reduce this problem. Less difficulty is encountered if the timber is green. Extra care is necessary when chiselling because of the soft nature of the wood, but there are no problems in boring. Some difficulty may be encountered in turning and sanding because of the fibrous nature of the wood and the tendency for raised grain. Sometimes, there is a slight though not readily apparent gum exudation from the wood which interferes with sanding. Usually there are no problems in gluing, screwing, painting or varnishing. The timber does not split when nailed and has good nail-holding properties. It can readily be peeled to various thicknesses without pretreatment. Veneer handling is easy, but veneer surfaces may be hairy or fuzzy. Good, smooth veneer can be obtained with a well sharpened knife using a bevel angle of 20°. Gluability of veneer is good.

Terentang is rated as non-durable; stake tests show an average service life in contact with the ground of only 5-6 months under tropical conditions. Under temperate conditions a longer service life is probably possible with proper drying. The timber is susceptible to sap-stain fungal infection. Though quite immune to powder-post beetle, a slight attack to the sapwood may occur. Fresh logs are reportedly susceptible to pinhole borer attack in the Solomon Islands. Terentang is not resistant to termites. It can be easily treated with preservatives and its absorption varies due to the presence of non-distinguishable sapwood.

The main constituent of "tigaso oil" is campnospermonol. The wood of C. auriculatum also contains an oil called "terentang oil"; it principally contains cyclohexenon derivates, and may be harmful to the human skin. The resin from the wood produces severe skin irritation in some people, similar to the exudate from rengas (Gluta and Melanorrhoea spp.).

Description

Small to large dioecious or polygamous trees (rarely shrubs), up to 50 m tall, but usually less, with bole up to 120(-220) cm in diameter, having small or no buttresses, sometimes with stilt roots, loop roots or pneumatophores when growing in swamps; outer bark smooth, shallowly irregularly fissured, scaly or papery flaky, usually cream, grey or yellowish-brown coloured, sometimes brown to almost black, inner bark usually red or reddish-brown, fibrous; main branches in tiers, with tendency to divide the bole into several large ascending limbs and to flat-topped crowns, twigs usually stout.
Leaves arranged spirally, clustered at ends of twigs, leathery, simple and entire, usually with minute scales on both surfaces, petioled or subsessile; stipules absent. Inflorescences axillary, paniculate, sometimes seemingly racemose.
Flowers unisexual, rarely bisexual, small and yellowish; calyx (3-)4(-5)-lobed; petals (3-)4(-5), free, imbricate, glabrous but sometimes with scales on outer surface; stamens twice the number of petals, inserted near the margin of a disk, epipetalous ones shorter than episepalous ones, with subulate and glabrous filaments and dorso-basifixed anthers; pistil 1, with a subglobose, 1-celled and scurfy ovary, a short or obscure style and a discoid stigma.
Fruit an ovoid or subglobose drupe, incompletely 2-celled by a vertical septum, ripening red to black.
Seed 1 per fruit, with testa free from endocarp, curved embryo and rather flat or slightly plano-convex cotyledons.

Wood anatomy

Macroscopic characters

Heartwood grey-pink or mauve-grey, not distinctly differentiated from the sapwood.
Sapwood becoming darker grey after long-term exposure.
Grain shallowly or deeply interlocked.
Texture very fine and even; planed surface without lustre or figure, but longitudinal surface mildly speckled by darker coloured rays.
Growth rings absent.
Vessels small, moderately numerous, tyloses and deposits absent.
Wood parenchyma not visible with a hand lens.
Rays very fine or fine, sometimes just visible to the naked eye, comparatively prominent on the radial surface.
Ripple marks absent.
Large horizontal intercellular canals clearly visible with a hand lens or to the naked eye.

Microscopic characters

Growth rings absent.
Vessels diffuse, 20-36(-40)/mm², solitary or in radial pairs and multiples of 3-4, rarely in tangential or oblique pairs or clusters, proportion of solitary vessels very variable, round to oval or slightly angular, average tangential diameter 60-125μm; perforations mixed simple and scalariform, multiple perforations with 6-36(-48) bars; intervessel pits alternate to opposite, locally sometimes scalariform, polygonal to elongate, 4-6(-10)μm; vessel-ray pits large and simple, horizontally to vertically elongate; tyloses absent or thin-walled and sporadic; deposits absent.
Fibres c. 1040-1480μm long, non-septate and septate, thin-walled, with simple to minutely bordered pits mainly confined to the radial walls.
Parenchyma extremely rare or absent.
Rays 4-11/mm, usually 1-3-seriate, but fusiform rays with radial canals wider, up to 1.0 mm high, heterocellular with 1-2 rows of square to upright marginal cells (Kribs type heterogeneous II to III) or homocellular.
Crystals and silica bodies absent.
Radial canals present.

Growth and development

The trees in the centre of pure stands on peat attain a mean bole diameter of only 25 cm and almost never exceed 40 cm, but towards the margin of the stands trees may attain 80 cm in diameter. Flowering and fruiting of trees are quite regular and frequent, and in many areas terentang has been found flowering throughout the year. The flowers, with their disks producing nectar, are evidently entomophilous. The fruits are eaten by birds, especially pigeons, which disperse the seeds. The fruits of trees growing in swampy forests or near rivers are also dispersed by water.

Other botanical information

The genus Campnosperma is often placed in the tribe Rhoeae, together with the genera Euroschinus, Parishia, Pentaspadon, Pistacia and Rhus. The leaves on vegetative shoots are usually much larger than those on fertile shoots. The smaller limbs and branchlets of terentang trees have a branching pattern which is very similar to Terminalia species. Terentang is sometimes associated with Terminalia species (e.g. Terminalia copelandii Elmer and T. brassii Exell) and these trees look very similar.

In Sri Lanka the timber of Campnosperma zeylanicum Thwaites is sometimes used for boxes.

Ecology

Terentang is often found in swampy lowland forests where it may form pure stands or be dominant or co-dominant. Sometimes open Campnosperma forest, often consisting of trees with sparse crowns and light bark, gives the impression of a forest of dead trees from the air. Throughout the humid tropical lowland of New Guinea terentang forest grows in permanent, stagnant and non-tidal freshwater swamps with undergrowth of sago (Metroxylon sagu Rottb.), pandans (Pandanus spp.), Thoracostachyum spp., Scleria spp. and Nepenthes spp., but in areas with lower annual rainfall terentang is replaced by Melaleuca spp. as the dominant trees. In terentang forest in New Guinea the soil is inundated up to 1.5 m for at least 5 months per year and at the end of the dry season the water table is nearly at soil level; peat formation occurs regularly. C. brevipetiolatum occurs up to 500 m altitude in areas with a uniform rainfall regime (mean annual rainfall 2000-5000 mm) and a mean annual temperature of 23-28°C (mean minimum temperature of coldest month: 20-24°C, mean maximum temperature of hottest month: 28-34°C). It grows on acid, preferably deep soils. It is a strongly light-demanding species.

In western Malesia terentang may also be co-dominant in freshwater swamps, sometimes even forming pure stands (e.g. in Peninsular Malaysia and Sumatra). In addition, terentang occurs in forests on well-drained soil, in primary as well as secondary forest, sometimes up to 1600 m altitude, particularly near streams and in valleys, and usually in low numbers.

Propagation and planting

The seeds show a short viability and need no pretreatment for germination. The weight of 1000 seeds of C. brevipetiolatum is approximately 400 g. The seedlings reach plantable size in 4 months.

Silviculture and management

Terentang demands strong light and regeneration is often abundant in regrowth forests where it has sufficient regeneration to maintain its present abundance.

C. brevipetiolatum has been one of the major species planted in the Solomon Islands, and as such is an important element of the reforestation and afforestation programmes.

Diseases and pests

Ambleypelta cocophaga causes death or dieback in young trees of C. brevipetiolatum.

Harvesting

A common defect of the timber is caused by small areas of spongy heart in some logs; sometimes minute compression failures or cross-breaks occur. The logs are liable to split through the pith but other forms of splits or checks and natural defects are uncommon.

Yield

The annual production of C. brevipetiolatum timber in planted forest in the Solomon Islands is 10-20 m³/ha.

Genetic resources

Outside swampy forests, terentang is not abundant in the forest and averages about one tree of commercial size per 12 ha. More than 2 trees per ha may occur in narrow belts near streams, but terentang might be liable to genetic erosion in these habitats. However, terentang is very common locally in freshwater and peat-swamp forest, and natural regeneration may be plentiful. Here genetic erosion seems to be much less likely.

Prospects

Terentang is a useful timber for light utility purposes because of its light weight. It is also a popular timber for peeling in Japan, and it is of interest to the Australian market because it is amenable to preservative treatment and is of low density. Terentang timber is regularly exported from Papua New Guinea and the Solomon Islands. In other countries like Malaysia, the supply is irregular and largely consumed by local industries. However, it may be assumed that in these countries, unlike other lightweight hardwoods such as meranti (from Shorea spp.), mersawa (from Anisoptera spp.), sepetir (from Sindora spp.), nyatoh (from Madhuca, Palaquium, Payena and Pouteria spp.) and jelutong (from Dyera costulata), terentang is exported under mixed light hardwood, which fetches a much lower price, comparatively. Unless sufficient research is done on, for instance, growth and yield of this timber, the role of terentang on the world market is not expected to increase.

Literature

Bolza, E. & Kloot, N.H., 1966. The mechanical properties of 81 New Guinea timbers. Division of Forest Products Technological Paper No 41. Commonwealth Scientific and Industrial Research Organization, Melbourne. pp. 12-15.
Ding Hou, 1978. Anacardiaceae. In: van Steenis, C.G.G.J. (Editor): Flora Malesiana. Ser. 1, Vol. 8. Sijthoff & Noordhoff International Publishers, Alphen aan den Rijn. pp. 524-532.
Eddowes, P.J., 1977. Commercial timbers of Papua New Guinea - their properties and uses. Forest Products Research Centre, Department of Primary Industry, Port Moresby.
Forest Research Institute Forestry Administration, 1984. The research reports of the Forest Research Institute No 31. Seoul. pp. 86-105.
Grewal, G.S., 1986. Malaysian timbers - terentang. Timber Trade Leaflet No 103. Malaysian Timber Industry Board, Forest Research Institute Malaysia. 8 pp.
Hegnauer, R., 1964. Chemotaxonomie der Pflanzen [Chemotaxonomy of plants]. Vol. 3. Birkhäuser Verlag, Basel and Stuttgart. pp. 90-115.
Keating, W.G. & Bolza, E., 1982. Characteristics, properties and uses of timbers. Vol. 1. South-East Asia, northern Australia and the Pacific. Inkata Press Proprietary Ltd., Melbourne. pp. 64-65.
Kochummen, K.M., 1989. Anacardiaceae. In: Ng, F.S.P. (Editor): Tree flora of Malaya. A manual for foresters. Vol. 4. Longman Malaysia SDN Berhad, Kuala Lumpur. pp. 18-20.
Ministry of Primary Industries, 1990. Statistics on forestry and timber. Kuala Lumpur.
van Royen, P., 1964. Manual of the forest trees of Papua and New Guinea. Vol. 4. Division of Botany, Department of Forests, Administration of Papua and New Guinea, Lae. pp. 15-19.

Selection of species

Authors

Ani Sulaiman (general part, properties, wood anatomy, selection of species)