Tetramerista (PROSEA)

Plant Resources of South-East Asia
Introduction

List of species

Tetramerista Miq.

Protologue: Fl. Ind. Bat., Suppl.: 534 (1861).

Family: Theaceae

Chromosome number: x= unknown

Trade groups

Punah: medium-heavy hardwood, a single species, Tetramerista glabra Miq., Fl. Ind. Bat., Suppl.: 534 (1861).

Vernacular names

Punah

Brunei: amat, entuyut, terepit
Indonesia: punak (general), kayu malaka (Sumatra), carega (Kalimantan)
Malaysia: tuyot (Sabah), entuyut, pokon hujun (Sarawak).

Origin and geographic distribution

The genus Tetramerista consists of 3 species. It is confined to western Malesia. T. glabra, the only species used for timber, occurs in Peninsular Malaysia, Singapore, Sumatra, Borneo (Sarawak, Brunei, Sabah, East Kalimantan) and adjacent islands.

Uses

Punah is a suitable timber for indoor construction. It is used for purlins, ceilings, flooring, posts, beams, door and window frames, and all other interior joinery and structural work not in contact with the ground. Punah is not particularly suitable for decorative purposes, e.g. for furniture. However, it is used for boxes and crates, and, when treated, for railway sleepers.

The tree produces a sour and fresh, red fruit which is used in fruit salads.

Production and international trade

Punah is a commercially important timber, although mostly only locally. No trade and export figures are available, but fairly large quantities of this timber are traded in Sumatra and Peninsular Malaysia. A small amount of timber is exported, e.g. to Japan. In East Kalimantan punah is often traded in combination with keruing (from Dipterocarpus spp.). In most coastal districts of Sarawak, Brunei, Sabah and East Kalimantan moderate supplies are available.

Properties

Punah is a moderately heavy and moderately hard timber. The heartwood is yellowish-pink, very light brown to straw-coloured when fresh, becoming slightly darker during drying, towards pinkish-brown, sometimes with splashes of orange-brown tinge or with darker coloured streaks. The sapwood is generally not differentiated from the heartwood when fresh but fairly well demarcated and lighter in colour when dry. The wood lathers when rubbed with water, and often contains a wax-like substance with an unpleasant smell when wet, but with a rather fragrant smell when dry. The density is 625-800 kg/m³ at 15% moisture content. The grain is straight, shallowly interlocked or spiral, texture coarse but even.

The modulus of rupture is 66-86 N/mm² for green timber and 87-105 N/mm² at 19% moisture content, the modulus of elasticity is 12 800-13 500 N/mm² in green condition, and 15 400-15 800 N/mm² at 19% moisture content and compression parallel to grain is 31.5-34.5 N/mm² in green condition and 49-64 N/mm² at 19% moisture content, compression perpendicular to grain c. 4 N/mm² in green condition and 5 N/mm² at 19% moisture content, shear c. 9 N/mm² when green and 10 N/mm² at 19% moisture content, cleavage c. 43 N/mm radial and 80 N/mm tangential at 19% moisture content; Janka side hardness is 4050-4320 N in green condition, and 4670-5220 N at 19% moisture content, Janka end hardness 4450 N at 75% moisture content. See also the table on wood properties.

The rates of shrinkage of punah are high, from green to 15% moisture content 3.2% radial and 4.5% tangential, from green to oven dry 6.1% radial and 10.7% tangential. Punah seasons fairly rapidly, but end and surface checks as well as splitting are recorded, and it is prone to sap stain. It takes 2.5 months to dry 15 mm thick boards to air-dry condition, 3.5 months for 25 mm thick boards and over 4 months for 40 mm thick boards. For drying, kiln schedule C (Malaysia) is recommended. The stock should be properly weighted down to reduce warping, and end-coating should be applied before kilning to reduce end splits.

Punah is easy to work. It saws easily, and blunting effects on tools are generally not severe, but sawteeth may become gummed up. Finish after planing and turning tends to be rough and fibrous; finishing requires considerable sanding. Boring and turning are rated as easy. It can be bored to a smooth finish with a two-winged, twist-fluted auger. The nail-holding capacity is good, but pre-boring for screwing is necessary to avoid splitting of thin boards. Punah glues well.

The timber is only moderately durable; stake tests show an average life of 3-4 years under tropical conditions. It is, however, rated as durable for interior work. Punah is liable to termite attack, and during seasoning a moderate amount of fungal staining is reported. The timber is moderately difficult to impregnate. Using the open tank system, the average absorption of a 1 : 1 mixture of creosote and diesel is 64-72 kg/m³, and 130 kg/m³ when using a pressure treatment. Other tests show figures of 111 kg/m³ and 145 kg/m³, respectively, for the same treatments. Treated railway sleepers have shown an average service life of 20 years.

The fine sawdust may cause allergic reactions.

Description

A medium-sized to fairly large tree up to 40 m tall, with straight bole up to 100(-150) cm in diameter and branchless up to 15 m, without distinct buttresses but ridged and fluted at the base; outer bark rough, shallowly and irregularly fissured, flaky, soft and thick, red-brown to dark brown, inner bark thick, up to 1.3 cm, soft and fibrous, pinkish-red outside to pinkish-cream inside; crown open, having a few large ascending branches and laterally spreading smaller branches; branchlets stout, rather pale.
Leaves alternately and arranged spirally, mostly more or less clustered near tips of twigs, simple and entire, oblanceolate to narrowly obovate, 6.5-30 cm × 3-8.5 cm, at base running down the short stalk and forming narrow wings, acute to notched at apex, leathery, glabrous and shiny, punctate with black glands beneath, with 12-20 pairs of secondary veins and faint or invisible tertiary venation, without stipules.
Inflorescence a long pedunculate axillary panicle or umbel-like raceme.
Flowers bisexual, actinomorphic, 2-2.5 cm across, with 2 sepal-like bracts at the base, 4-merous; sepals oblong, petals lanceolate, about as long as sepals; stamens with filaments flattened at the base and oblong-sagittate anthers glandular at base; ovary 4-locular, each locus with a single ovule.
Fruit a globose to ellipsoid berry, c. 3 cm × 2.5 cm, surrounded at the base by the persistent bracteoles, sepals and petals, 4-seeded.
Seeds oblong, 1-2 cm long.
Seedling with epigeal germination.

Wood anatomy

Macroscopic characters

Sapwood not defined from heartwood when fresh but fairly clearly demarcated in seasoned timber; heartwood straw-coloured or yellow-pink, weathering to a pink-brown with an orange-brown tinge.
Grain straight, shallowly interlocked or spiral.
Texture coarse but even.
Planed surface rather dull (without lustre).
Growth rings absent; vessels visible to the naked eye and sparsely filled with tyloses; pinkish deposits common; rays of two distinct sizes, the broader rays distinct to the naked eye and conspicuous on the radial surface.

Microscopic characters

Growth rings absent.
Vessels diffuse, 2-3/mm², mainly in multiples of 2-6 or more, rarely solitary or in clusters, multiples sometimes with narrow and short radial tails, oval to polygonal, average tangential diameter 200 μm or more; perforations mostly simple, occasionally scalariform; intervessel pits alternate, minute and round, 2-6 μm; vessel-ray and vessel-parenchyma pits similar but half-bordered; helical thickenings absent; reddish-brown gum-like deposits present; tyloses infrequent.
Fibres 2000-3300 μm long, non-septate, mostly thick-walled, with simple to minutely bordered pits mainly confined to the radial walls. Parenchyma abundant, apotracheal, diffuse or diffuse-in-aggregates, in 4-8-celled strands.
Rays, about 10/mm, of two distinct sizes, 1(-2)-seriate and 4-5-seriate (rarely more), broad rays often several mm high, mostly Kribs type heterogeneous I with up to 10 to very many marginal rows of square to upright cells.
Raphides often present in enlarged procumbent cells in the multiseriate rays.
All elements non-storied.

Growth and development

The growth of seedlings and saplings is reported to be fairly rapid. In Peninsular Malaysia punah has been found flowering and fruiting throughout the year.

Other botanical information

Punah is the only commercially important timber tree species of the genus Tetramerista. The genus was formerly included in either Ochnaceae, Marcgraviaceae, Ternstroemiaceae or treated as a separate family Tetrameristaceae. Until the taxonomic relationships within the rather heterogeneous family of Theaceae have been unravelled, it seems best to be conservative and to treat the genus as a member of this family. Sterile specimens of punah may be mistaken for Dillenia spp., Campnosperma spp. or Tristania spp. Punah may be vegetatively distinguished from these species by the completely entire margin of the leaf, the very faint or invisible tertiary venation and the lack of intramarginal veins.

Ecology

Punah grows in lowland forest, generally in freshwater or peat-swamp forest, and occasionally in "kerangas" (heath forest) vegetation, on sites where the soil is waterlogged and is fibrous and peaty, or on podzols. The tree obviously demands a strongly acid soil. It is a typical inhabitant of coastal dipterocarp swamp forest.

Propagation and planting

Natural regeneration from seeds is often quite abundant, but only a few seedlings survive. Seeds have delayed germination, germinating after 13-36 weeks.

Silviculture and management

The management system used for mixed dipterocarp forest may be successfully put into practice for punah. In swamp forest in western Peninsular Malaysia, Sumatra and Sarawak, punah is locally common, in some areas averaging 1 large tree per ha, but stands of 5-8 trees of commercial size per ha may occur. However, in most areas punah occurs very scattered. Young trees are reported to coppice freely.

Diseases and pests

Densely congested inflorescences with tiny gall flowers are often found, probably caused by insects or viruses.

Harvesting

Severe heartwood shakes may occur when the trees are felled. These shakes become rapidly filled with a wax-like substance which is dark and acid and causes an unpleasant smell.

Fresh logs are sinkers, so have to be transported over land or fastened to floating logs when transported by river.

Genetic resources

Punah is a valuable timber, but if it is cut without a good management system, this species may be liable to genetic erosion as it is only locally common and abundant and is ecologically restricted.

Prospects

Punah is a poorly studied timber species. Research on silvicultural aspects is particularly urgently needed. Punah may be a promising species for planting in swamp areas.

Literature

Browne, F.G., 1955. Forest trees of Sarawak and Brunei and their products. Government Printing Office, Kuching. pp. 259-260.
Burgess, P.F., 1966. Timbers of Sabah. Sabah Forest Records No 6. Forest Department, Sabah, Sandakan. pp. 468-469.
Chudnoff, M., 1979. Tropical timbers of the world. USDA, U.S. Forest Products Laboratory, Madison, Wisconsin. pp. 757-758.
Foxworthy, F.W., 1927. Commercial timber trees of the Malay Peninsula. Malayan Forest Records No 3. Forest Department, Kuala Lumpur. pp. 171-172.
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, Sydney and London. p. 341.
Keng, H., 1989. Tetrameristaceae. In: Ng, F.S.P. (Editor): Tree flora of Malaya. A manual for foresters. Vol. 4. Malayan Forest Records No 26. Longman Malaysia SDN Berhad, Kuala Lumpur. pp. 470-471.
Lopez, D.T., 1982. Malaysian timbers - punah. Malaysian Forest Service Trade Leaflet No 59. Malaysian Timber Industry Board, Kuala Lumpur. 6 pp.
Research Institute of Wood Industry, 1988. Identification, properties and uses of some Southeast Asian woods. Chinese Academy of Forestry, Wan Shou Shan, Beijing and International Tropical Timber Organization, Yokohama. p. 189.
Singh, G., 1971. Report on the kiln drying experiment on punah (Tetramerista spp.). Malayan Forester 34: 299-302.
Timber Research and Development Association, 1979. Timbers of the world. Vol. 1. The Construction Press, Lancaster. pp. 399-400.

Other selected sources

102, 146, 159, 190, 318, 334, 416, 448, 508, 581, 694, 781.

Authors

K. Sidiyasa (general part),
W.G. Keating (properties),
S.C. Lim (wood anatomy)