Changes

:Chromosome number: ''x''= unknown;''P. gutta'': 2''n''= 24

'''== Trade groups'''==

*'''Nyatoh''': lightweight to medium-heavy hardwood, e.g. ''Palaquium amboinense'' Burck, ''P. burckii'' H.J. Lam, ''P. hexandrum'' (Griffith) Baillon, ''P. luzoniense'' (Fernandez-Villar) S. Vidal, ''P. maingayi'' (C.B. Clarke) King & Gamble, ''P. microphyllum'' King & Gamble, ''P. obovatum'' (Griffith) Engl., ''P. obtusifolium'' Burck, ''P. rostratum'' (Miq.) Burck, ''P. xanthochymum'' (de Vriese) Pierre ex Burck.

*'''Bitis''': heavy hardwood, e.g. ''P. ridleyi'' King & Gamble, ''P. stellatum'' King & Gamble.

*'''Nyatoh: '''*padang (En)

*'''Bitis'''

The genus ''Palaquium'' consists of about 110 species and is distributed from western India and Sri Lanka to southern China and east to Polynesia (Samoa). The centre of diversity is western Malesia; most species are found in the Philippines (about 30) and Borneo (about 35), many of them endemic. Peninsular Malaysia and Sumatra are somewhat less rich in species (about 20). New Guinea is considered an important secondary centre of diversity with about 13 species. The most widely distributed species are ''P.'' ''amboinense'' and ''P.'' ''obtusifolium'' (western Indonesia to New Guinea), ''P.'' ''obovatum'' (India to the Philippines and the Moluccas) and ''P.'' ''ridleyi'' (Indo-China to New Guinea).

Gutta-percha, i.e. latex from ''Palaquium'' trees, especially ''P.'' ''gutta'' , has been praised for its insulating property and imperviousness to water. As such, it has been in demand for the insulation of subterranean and submarine electrical cables. It has also been used in the manufacture of golf balls, certain types of surgical appliances, transmission bells, and acid-resistant receptacles. Other uses have included splints for fractures, supports, pipes, speaking tubes, in telephone receivers, as adhesives and an ingredient of chewing gum. At present its main application is for protecting wounds and in dental clinics, where it is proving to be useful for people allergic to synthetic fillers.

The fruits of several species (e.g. ''P. burckii, P. eriocalyx'' H.J. Lam, ''P. hexandrum, P. lanceolatum, P. macrocarpum, P. philippense, P. rostratum, P. stellatum'' and ''P. walsurifolium'' ) are edible. The seeds often contain a fat which is used for cooking or as an illuminant, and is sometimes used for the manufacture of soap and vegetable butter.

Timber from ''Palaquium'' species is usually traded as nyatoh together with the timber of other ''Sapotaceae'' genera, particularly ''Payena'' , ''Pouteria'' and ''Madhuca'' . However, in many places ''Palaquium'' species supply the bulk of the timber sold as nyatoh. The export of nyatoh sawn timber from Peninsular Malaysia decreased from 16 500 m³(with a value of US$ 2.1 million) in 1981 to 9500 m³(with a value of US$ 1.3 million) in 1986. From 1986 onward the export increased to 32 500 m³with a value of US$ 6.1 million in 1990, but in 1992 it was only 8000 m³with a value of US$ 2.8 million. Large amounts of nyatoh are also exported from Sarawak and Sabah; the export of round logs from Sabah was 65 000 m³(worth US$ 6.3 million) in 1987, and in 1992 the export was 14 000 m³of logs and 8500 m³of sawn timber with a total value of US$ 4.4 million. In Papua New Guinea nyatoh is ranked in MEP (Minimum Export Price) group 1, and fetched a minimum export price of US$ 100/m³for saw logs in 1992.

Timbers of the bitis class are usually converted to scantling sizes, and sold unclassified. The bulk of the "seriah" sold in Singapore consists of logs of ''Palaquium'' and ''Payena'' , and probably other Sapotaceous trees imported from Indonesia.

Some ''Palaquium'' species have latex in sufficient amounts to make them commercially important in gutta-percha trade. The best grade of gutta-percha is produced by ''P.'' ''gutta'' . International trading in gutta-percha, in particular to Europe, started in the second half of the 19th Century with Singapore as the centre. After the trees around Singapore were felled the search for gutta-percha quickly extended northward into Peninsular Malaysia, and south and east into Indonesia, through the Riau Archipelago to Kalimantan, to Sarawak and Sabah and ultimately to the Philippines. Export of Indonesian gutta-percha is mainly to Singapore (93%) and to a much lesser extent to the United States, Germany, Britain and Hong Kong. The total gutta-percha potential of Indonesia is estimated at 10 000 t/year, most of it present in Kalimantan (38%), South Sumatra (23%) and South Sulawesi (23%). However, trade in gutta-percha has decreased drastically due to the replacement by synthetic plastics.

A general description of nyatoh and bitis is given here. ''Palaquium'' timber with its density of (400-)450-1120 kg/m³at 15% moisture content is classified in both groups, depending on the weight of the timber; the arbitrary limit between the groups lies at 850 kg/m³.

Nyatoh is a light to medium-weight, moderately hard to hard red meranti-like wood. The heartwood is pinkish-brown to reddish-brown and only moderately distinct from the lighter sapwood. The density is (420-)550-800(-850) kg/m³at 15% moisture content; that of the majority of the commercial supply is 600-700 kg/m³. The grain is shallowly interlocked, texture moderately fine and even.

The sawing properties are variable, probably depending on the species; but variation may be large within species too. Some nyatoh-producing species contain silica, which makes the timber difficult to work (e.g. ''P.'' ''gutta'' and ''P. walsurifolium'' ). Gum may clog cutters. Nyatoh is easy to polish when the grain is properly filled. The wood is easy to turn. Pre-boring for nails and screws is advised because of easy splitting. Gluing is trouble-free. The fine grain and colour make it suitable for veneer; it can be peeled at a 91peeling 91° peeling angle without pretreatment. Sometimes the wood is figured and then the veneer can be very attractive, especially when radially sliced. Peeling is reported as easy to fairly difficult, and a good plywood can be made from the timber. The logs are reasonably free from defects.

Nyatoh is rated as only moderately durable. It is prone to termite attack and susceptible to fungal attack, but not to powder-post beetles. Treated nyatoh timber can be very durable. However, it is very resistant to preservative treatment. Using the open tank method and an equal mixture of creosote and diesel, the heartwood absorbs on average only about 11 kg/m³. Bitis comprises heavier timber, with density of 850-1150 kg/m³at 15% moisture content. The heartwood is reddish-brown to dark brown, and clearly differentiated from the lighter sapwood. The grain is fairly straight, texture moderately fine and even. Bitis is very hard and strong, and much more durable than nyatoh.

Gutta-percha is a non-elastic rubber derived from the latex. The fresh greyish-white latex turns reddish-brown when exposed to the air. It is then a marble-like solid mass. In contrast, pure gutta-percha is colourless and translucent when sliced thinly. At 25C 25° C it becomes pliable and it gradually softens upon heating. At 60C60° C, it is so plastic that it can be drawn into threads of any form. The hardest gutta-percha will soften at 65C65° C. Insoluble in cold water, gutta-percha dissolves easily in benzene, carbon disulphide, chloroform and all solvents of rubber. Concentrated alkalies, dilute acids and even hydrofluoric acid do not affect the composition of gutta-percha. ''P.'' ''gutta'' gives the best quality of gutta-percha, containing up to 80% poly-isoprene and then only 20% resin. Many other ''Sapotaceae'' trees may also provide gutta-percha, but the proportion of poly-isoprene and resin is usually much less favourable.

*Small to very large trees, with latex, sometimes up to 60 m tall, usually with columnar buttressed bole up to 130(-250) cm in diameter, often branchless for a considerable length; outer bark smooth, cracked or fissured, usually brown to reddish-brown, inner bark soft and fibrous, pinkish-yellow, pink, red or reddish-brown; twigs usually slender (but massive in ''P.'' ''clarkeanum'' ), often hairy or scurfy at least at tips, often with distinctly developed terminal cone-like buds. *Leaves arranged spirally, usually densely to loosely clustered at ends of twigs, simple and entire, usually obovate, generally glabrous above and more or less hairy beneath when mature; secondary veins straight, curving towards apex and often joined near leaf margin, tertiary veins transverse or parallel to secondary ones or reticulate; petiole usually of even thickness throughout its length; stipules small to large, usually early caducous, rarely absent. *Inflorescence an axillary or rarely terminal fascicle, 1-many-flowered. *Flowers bisexual or rarely unisexual; sepals (4-)6(-7), generally in two whorls of 3, ovate or triangular; corolla (5-)6-lobed, with usually short tube and imbricate, often contort lobes, white to yellowish or greenish; stamens (10-)12-18(-36), inserted at the throat of the corolla tube, with acute anthers; pistil 1, with (5-)6(-10)-celled ovary and usually long style. *Fruit a berry with fleshy pericarp, 1-3-seeded. *Seed with a crustaceous to coriaceous testa and a large hilum often covering up to two-thirds of the surface of the seed, rarely hilum narrow (e.g. ''P.'' ''ridleyi'' , ''P.'' ''stellatum'' ); endosperm usually absent and cotyledons thick and fleshy, but rarely endosperm abundant and cotyledons thin (e.g. ''P.'' ''ridleyi'' ). *Seedling usually with epigeal germination (sometimes hypogeal, e.g. ''P.'' ''gutta'' and ''P.'' ''obovatum'' ), with strongly developed taproot; first pair of leaves opposite or subopposite, subsequent leaves arranged spirally and soon similar to leaves of adult trees.

*Heartwood deep pink, red, red-brown or purple-brown, sometimes with dark streaks, distinctly to indistinctly demarcated from the pale red sapwood, sometimes with a sour smell when freshly sawn. *Grain shallowly to moderately interlocked, sometimes wavy. *Texture moderately fine to coarse; wood dull, sometimes glossy. *Growth rings indistinct to vaguely visible; vessels and parenchyma indistinct to barely visible to the naked eye; rays and parenchyma not distinct without a lens.

*Growth rings indistinct, if present marked by differences in spacing of tangential parenchyma bands, and/or in fibre wall thickness on either side of the ring boundary. *Vessels diffuse, 6-14/mm², mainly in radial multiples of 2-5(-8), sometimes in a radial or radial to oblique pattern, round to oval, average tangential diameter 100-220μm220 μm; perforations simple; intervessel pits alternate, round, (4-)6-8μm; vessel-ray pits mainly confined to the upright and square cells, mostly large and simple, horizontally to vertically elongated or round, partly half-bordered, scarce in procumbent cells; helical thickenings absent; gum-like deposits and thin-walled tyloses sometimes present. *Fibres generally 1000-2100μm 2100 μm long, non-septate, mostly medium thick-walled, but ranging from very thin- to very thick-walled, with simple to minutely bordered pits mainly confined to the radial walls. *Parenchyma abundant, diffuse, diffuse-in-aggregates or in fine discontinuous to continuous 1-2(-3)-seriate straight to slightly wavy bands forming a reticulate pattern, 4-8 lines per radial mm, in 6-8(-10)-celled strands. *Rays 8-12(-15)/mm, 1-2(-3)-seriate with uniseriate tails, in some species mainly uniseriate, in others mainly multiseriate, up to 900μm high, heterocellular with (1-)2-5(-8) rows of upright and square marginal cells and procumbent body cells. *In some species crystals recorded in chambered axial parenchyma in chains of up to 8 cells. *Silica bodies present in ray cells of most species.

Species studied: ''P. amboinense, P. ellipticum'' (Dalzell) Baillon , '', P. gutta, P. hexandrum, P. leiocarpum'' , ''P. lobbianum'' , ''P. luzoniense, P. maingayi, P. microphyllum, P. obovatum, P. obtusifolium, P. polyanthum'' (Wallich) Baillon , '', P. ridleyi, P. rostratum, P. semaram'' , ''P. stellatum, P. walsurifolium, P. xanthochymum.xanthochymu''.

The few data available show a slow rate of growth. In Peninsular Malaysia the mean annual girth increment for ''P.'' ''maingayi'' and ''P.'' ''rostratum'' is only 1.5 cm and 1.8 cm, respectively; these trees take 100 and 70 years respectively, to attain a diameter of 55 cm. However, a ''P. rostratum'' tree in an arboretum attained a diameter of 57 cm in 40 years. ''P.'' ''gutta'' has a mean annual girth increment of 3.8 cm and attains about 8 m height in 7 years, 17 m in 23 years and a diameter of about 50 cm in 50 years.

Most ''Palaquium'' species grow in lowland forest. Only occasionally are species found at higher elevations, e.g. ''P.'' ''regina-montium'' in Peninsular Malaysia and ''P.'' ''rioense'' in Borneo. Usually the trees occur scattered in the forest; rarely ''Palaquium'' species form almost pure stands, e.g. ''P.'' ''xanthochymum'' locally in Peninsular Malaysia. Many species are common in freshwater swamp forests, some grow commonly in peat swamps, e.g. ''P.'' ''ridleyi'' and ''P.'' ''maingayi'' .

'''== Silviculture and management''' == Natural regeneration of ''Palaquium'' trees is often plentiful in secondary or logged-over forests. The enrichment planting system ensures sufficient regeneration in natural forests, but the saplings are often poorly competitive. ''Palaquium'' trees need a considerable amount of light for optimal development. Trees freed by cutting away the overshadowing vegetation show much increased vigour.

''Palaquium'' trees are susceptible to the fungus jamur upas ( ''Corticium'' ''salmonicolor'' ).

In timber concession areas in the Riau Archipelago and Sumatra, suntai ( ''Palaquium'' ''burckii'' ) is placed in the same timber group as meranti ( ''Shorea'' spp.), punah ( ''Tetramerista'' ''glabra'' Miq.) and pulai ( ''Alstonia'' spp.).

At 60C60° C, gutta-percha can be moulded into a desired shape, which is retained on cooling. Gutta-percha is usually transported and traded in vacuum zinc containers.

* van Royen, P., 1960. Revision of the Sapotaceae of the Malaysian area in a wider sense 23. Palaquium Blanco. Blumea 10: 432-606. | '''10''' | * Wong, T.M., 1981. Malaysian timbers - nyatoh. Malaysian Forest Service Trade Leaflet No 54. Malaysian Timber Industry Board, Kuala Lumpur. 12 pp. == Selection of species ==