30

5(2): Timber trees; Minor commercial timbers

Wrightia R.Br.

On Asclepiad.: 762 (1810).

APOCYNACEAE

x = 11; Wrightia arborea and some species from India: 2n = 22

Trade groups Lanete: lightweight to medium-weight hardwood: Wrightia arborea (Dennst.) Mabberley, Wrightia laevis Hook.f., Wrightia pubescens R.Br.

Lanete (Philippines). Indonesia: mentaos (Javanese), bintaos (Sundanese). Malaysia: jeliti. Thailand: mok-man. Vietnam: m[uws]c, th[uwf]ng.

Wrightia consists of 26 species which are confined to the Old World tropics. They occur from East Africa through India, Burma (Myanmar), Indo-China, southern China, Thailand and the Malesian region (probably excluding Borneo) eastwards towards the Solomon Islands and north-eastern Australia. Most of the species are found in India and Indo-China, and only 5 in the Malesian area.

Lanete wood is used especially for carving, but also for furniture, funnel products, and veneer. It is used for carved fancy boxes, musical instruments, cabinet work, picture frames, inlaying, kitchen utensils, chairs, chests, turnery, window sills, scabbards, wooden shoes, chopsticks, parang sheaths and blowpipe mouths. The wood of Wrightia tinctoria R.Br. is used extensively in India for carving and lacquer work for toys; it is becoming scarce.
The plants have medicinal properties and are used locally against e.g. eye diseases and dysentery. The bark of Wrightia arborea is reported to be useful as antidote to snake bite and scorpion sting; it is also used in local medicine. An indigo-yielding glucoside present in the seeds, roots and leaves of several species is used for dyeing in India and Indo-China. Sap of Wrightia tinctoria from India added to milk reportedly has preservative properties; the milk will remain fresh for some time, the taste remaining unaltered. The bark of Wrightia pubescens has milk-clotting properties and is used in Indonesia in the preparation of 'litsusu', a cheese-like product. Several species of Wrightia are planted as ornamentals, and in the Philippines Wrightia pubescens is used for reforestation.

If lanete is traded as logs or sawn timber, only very small amounts are involved. The dimensions of the timber are usually too small to make it important on the international market. In the Philippines, it reaches the market in the form of small logs 20-30 cm in diameter and 1.5-2 m long. It is usually processed locally and particularly used for carving. In Bali, the estimated demand of wood for this purpose is 420 m³/year. No statistics are available on the trade of products made from lanete wood.

Lanete is a lightweight to medium-weight and rather soft to moderately hard wood. The heartwood is creamy white to pale yellow, sometimes with a pinkish tinge, and not clearly demarcated from the sapwood. The density is 410-620(-785) kg/m³ at 15% moisture content. The grain is straight to slightly interlocked, texture fine to very fine; the wood is glossy.
A test of Wrightia arborea wood in Thailand at 14% moisture content showed the following mechanical properties: the modulus of rupture 90 N/mm², modulus of elasticity 6575 N/mm², compression parallel to grain 35 N/mm², compression perpendicular to grain 8 N/mm², shear 17.5 N/mm², and Janka side hardness 4765-5000 N.
The timber air dries well without serious degrade, but rapid drying is necessary to prevent blue stain or sap staining. Treatment with the preservatives sodium pentachlorophenate, cuprisulphate and sodium tetraborate has been unsatisfactory. The wood is easy to work; it carves and turns particularly well. It is not durable when exposed to the weather or in contact with the ground, and is susceptible to termite attack. However, wood of Wrightia pubescens from the Philippines is reported to be moderately resistant to termite and powder-post beetle attack.

Deciduous or evergreen shrubs or small to fairly large trees, up to 40 m tall, rarely climbers; bole cylindrical, straight, occasionally crooked, up to 60 cm in diameter, not buttressed but often fluted at base; bark surface fissured longitudinally, pale grey to yellowish-brown, inner bark granular or fibrous, yellow, exuding milky latex; branchlets glabrous or puberulous, with elliptical, white or greyish lenticels. Leaves decussate, simple, entire, pinnately veined, petiolate to subsessile; petiole bearing few to numerous pectinate glands in its axil, leaf blade eglandulose; stipules absent. Inflorescence terminal or axillary, aggregated dichasial to monochasial. Flowers actinomorphic, bisexual, 5-merous, usually fragrant; calyx deeply divided, lobes imbricate; corolla with a cylindrical to campanulate tube, lobes overlapping to the left, with a conspicuous and variously shaped corona; disk absent; stamens inserted on the corolla tube, epipetalous, anthers narrow, coherent into a cone and adherent to the stigma; ovary superior, consisting of 2 free or slightly connate carpels, united towards the apex by the style, pistil head subcapitate or subcylindrical, provided with a basal collar. Fruit consisting of a pair of pendulous follicles completely connate or connate only at the very base, terete or compressed, dehiscent throughout by an adaxial suture. Seeds many per follicle, narrowly fusiform, with a basal tuft of hairs; embryo erect; cotyledons broad and convolute. Seedling with epigeal germination; cotyledons leafy; hypocotyl elongated; all leaves opposite.

- Macroscopic characters: Heartwood whitish to pale yellow, not distinctly demarcated from the sapwood. Grain straight or shallowly interlocked. Texture fine; wood surfaces lustrous. Growth rings not distinct; vessels small and only visible with a hand lens; parenchyma and rays not visible with the naked eye; parenchyma visible with hand lens on moist surfaces.
- Microscopic characters: Growth rings absent or indistinct and then marked by differences in fibre diameter and wall thickness. Vessels diffuse, usually 17-25(- 28)/mm², solitary and predominantly in radial multiples of 2-5(-8), 70-90(-100) µm in tangential diameter; perforations simple; intervessel pits alternate, vestured, fine, c. 3 µm in diameter; vessel-ray and vessel-parenchyma pits almost similar to intervessel pits but half-bordered; tyloses absent. Fibres 0.9-1.4 mm long, non-septate, ranging from very thin-walled to thick-walled, walls usually c. 3 µm thick, with slit-like pits with minute borders and more numerous in the radial than in the tangential walls. Parenchyma apotracheal, diffuse-in-aggregates, abundant, mostly in 8-celled strands. Rays 12-18/mm, 1-2(-3)-seriate, 450-2000(-2800) µm high, markedly heterocellular with more than 4 rows of upright marginal cells and multiseriate portions almost as narrow as the much taller-celled uniseriate ones (Kribs type heterogeneous I, sometimes II). Crystals prismatic, elongated and styloid, in chambered cells, up to 30 in radial chains, in upright and procumbent ray cells. Latex tubes absent.
Species studied: Wrightia laevis, Wrightia pubescens.

Lanete trees exhibit Troll's architectural model. The leader shoot of the seedling bends over after 3-5 nodes and becomes plagiotropic. New shoots are produced on top of each other (continual superposition) and each shoot adds a little to the height before becoming plagiotropic. The axes contribute partly to the trunk, partly to branches. The basal part of each shoot becomes erect after leaf fall, by secondary growth.
In natural forest in India, Wrightia arborea grows 7.5-25 cm during the first year, but subsequent growth is more rapid. If young trees are watered regularly and are free from weed competition, they may grow up to 115 cm in the first year. After three years, untended plants are 80 cm tall, whereas plants benefiting from regular watering and weeding are up to 3.9 m tall. The mean annual diameter increment of Wrightia arborea in India is 0.4-0.8 cm.
Well-tended plants of Wrightia arborea start producing viable seed after three years. The plumose seeds are dispersed by wind.

Wrightia belongs to the tribe Nerieae of the subfamily Apocynoideae and is most closely related to the genus Pleioceras. It differs from the latter by e.g. its dichasial or monochasial inflorescence, the glabrous mouth of its corolla tube, and its comparatively short and simple alternating supplementary corona segments. Pleioceras has its flowers in thyrses and the corolla tube has a pubescent mouth. It has long and compound alternating supplementary corona segments.

Lanete is found in a variety of habitats, ranging from evergreen rain forest to savanna and thickets along the beach. The altitudinal range is from sea-level to 1800 m. The timber-producing species are generally found in lowland or hill evergreen to deciduous primary or secondary forest, or sometimes in thickets. Wrightia arborea is found in areas with an annual rainfall of 875-3750 mm; it is a moderate light demander.

Wrightia can be propagated by seed in the nursery or by direct sowing. The latter was successful in India for Wrightia arborea. As seed is dispersed by wind, the fruits should be collected from the trees. One fruit contains 30-40 seeds and in Wrightia arborea there are 53 000-60 000 seeds/kg. It may not be possible to store seed for longer periods: Wrightia arborea seeds in India lose viability after one year. Fresh seeds display a high viability and germinate rapidly; the germination period for Wrightia religiosa (Teijsm. & Binnend.) Benth. (a shrub-like species) in Malaysia is 10-14 days. Special care must be taken when planting seedlings out in the field, as plants may easily die back or die completely.

In general, lanete tolerates drought fairly well. Natural regeneration is often plentiful and is best on loose ground where weeds are absent. Plants suffer seriously from weeds and weeding seems a prerequisite for good plantation establishment. Wrightia arborea coppices well and recovers well after frost damage, as has been observed in India.

In India, the fungus Cercospora wrightia causes leaf spot disease of Wrightia tinctoria.

Several Wrightia species are becoming scarce as the wood is in demand for carving. Wrightia pubescens subsp. laniti is considered to be a vanishing timber species in the Philippines and the wood of Wrightia pubescens subsp. pubescens is reportedly becoming scarce in Bali where it is used for handicrafts. Wrightia tinctoria stands have been depleted in India. However, in other areas such as Vietnam, lanete is regarded less at risk of genetic erosion as it is widespread and regenerates easily.

Lanete may have for small-scale and local planting in South-East Asia. It is comparatively easy to propagate, grows fairly rapidly, the wood is suitable for handicrafts and sculptures, and the trees can also be used for other purposes such as reforestation and as an ornamental.

de Guzman, E.D., Umali, R.M. & Sotalbo, E.D., 1986. Guide to Philippine flora and fauna. Vol. 3: dipterocarps, non- dipterocarps. Natural Resources Management Center, Ministry of Natural Resources and University of the Philippines, Manila. pp. 353-354.
Hall‚, F., Oldeman, R.A.A. & Tomlinson, P.B., 1978. Tropical trees and forests. An architectural analysis. Springer-Verlag, Berlin, Heidelberg, New York. p. 249.
Ingle, H.D. & Dadswell, H.E., 1953. The anatomy of the timbers of the south-west Pacific area. II. Apocynaceae and Annonaceae. Australian Journal of Botany 1: 10-11.
Meniado, J.A., America, W.M., de Vela, B.C., Tamolang, F.N. & Lopez, F.R., 1981. Wood identification handbook for Philippine timbers. Vol. 2. Apo Production Unit, Quezon City. pp. 19-21.
Ng, F.S.P., 1991. Manual of forest fruits, seeds and seedlings. Vol. 1. Malayan Forest Records No 34. Forest Research Institute Malaysia, Kepong. pp. 25, 141.
Ngan, P.T., 1965. A revision of the genus Wrightia (Apocynaceae). Annals of the Missouri Botanical Garden 52: 114-175.
Reyes, L.J., 1938. Philippine woods. Technical Bulletin 7. Commonwealth of the Philippines, Department of Agriculture and Commerce. Bureau of Printing, Manila. pp. 419-421.
Tran Dinh Ly, 1986. Die Familie Apocynaceae Juss. in Vietnam. Teil 3: Spezieller Teil (2) [The family of the Apocynaceae Juss. in Vietnam. Part 3: Special Part (2)]. Feddes Repertorium 97: 619-627.
Troup, R.S., 1921. The silviculture of Indian trees. Vol. 2: Leguminosae (Caesalpinieae) to Verbenaceae. Clarendon Press, Oxford. pp. 668-671.
Whitford, H.N., 1911. The forests of the Philippines. Part II: the principal forest trees. Bureau of Forestry, Bulletin No 10. Bureau of Printing, Manila. p. 96.

Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. 2nd edition. Ministry of Agriculture and Co-operatives, Kuala Lumpur. Vol. 1 (A-H) pp. 1-1240. Vol. 2 (I-Z) pp. 1241-2444.
de Guzman, E.D., 1975. Conservation of vanishing timber species in the Philippines. In: Williams, J.T., Lamoureux, C.H. & Wulijarni-Soetjipto, N. (Editors): South East Asian plant genetic resources. Proceedings of a Symposium on South East Asian Plant Genetic Resources held at Kopo, Cisarua, 20-22 March 1975. International Board for Plant Genetic Resources, SEAMEO Regional Center for Tropical Biology/BIOTROP, Badan Penelitian dan Pengembangan Pertanian and Lembaga Biologi Nasional - LIPI, Bogor. pp. 198-204.
de Guzman, E.D., Umali, R.M. & Sotalbo, E.D., 1986. Guide to the Philippine flora and fauna. Vol. 3: Dipterocarps, non-dipterocarps. Natural Resources Management Centre, Ministry of Natural Resources, Quezon City & University of the Philippines, Los Baños. xx + 414 pp.
Heyne, K., 1927. De nuttige planten van Nederlands-Indië [The useful plants of the Dutch East Indies]. 2nd edition, 3 volumes. Departement van Landbouw, Nijverheid en Handel in Nederlandsch-Indië, 's-Gravenhage. 1953 pp.
Ingle, H.D. & Dadswell, H.E., 1953. The anatomy of the timbers of the south-west Pacific area. II. Apocynaceae and Annonaceae. Australian Journal of Botany 1: 10-11.
Koorders, S.H. & Valeton, T., 1894-1915. Bijdrage tot de kennis der boomsoorten van Java [Contribution to the knowledge of the tree species of Java]. 13 parts. G. Kolff & Co., Batavia, 's-Gravenhage.
Meniado, J.A. et al., 1975-1981. Wood identification handbook for Philippine timbers. 2 volumes. Government Printing Office, Manila. 370 pp. & 186 pp.
Ngan, P.T., 1965. A revision of the genus Wrightia (Apocynaceae). Annals of the Missouri Botanical Garden 52: 114-175.
Pham Hoang Ho, 1993. An illustrated flora of Vietnam. Vol. II(2). Mekong Publisher, Montreal.
Reyes, L.J., 1938. Philippine woods. Technical Bulletin No 7. Commonwealth of the Philppines, Department of Agriculture and Commerce. Bureau of Printing, Manila. 536 pp. + 88 plates.
Smitinand, T., 1980. Thai plant names. Royal Forest Department, Bangkok. 379 pp.
Tantra, I.G.M., 1987. Kayu kurang dikenal yang mungkin dipasarkan di Bali untuk kerajinan [The possibilities for marketing lesser-known tree species in Bali for handicrafts]. In: Prosiding diskusi pemanfaatan kayu kurang dikenal, 13-14 Januari 1987, Cisarua, Bogor. Badan Penelitian dan Pengembangan Kehutanan, Bogor. pp. 335-336.
Tran Dinh Ly, 1986. Die Familie Apocynaceae Juss. in Vietnam. Teil 3: Spezieller Teil (2) [The family of the Apocynaceae Juss. in Vietnam. Part 3: special part (2)]. Feddes Repertorium 97: 607-689.
Weidelt, H.J. (Editor), 1976. Manual of reforestation and erosion control for the Philippines. Schriftenreihe No 22. Deutsche Gessellschaft für Technische Zusammenarbeit )GTZ) GmbH, Eschborn. 569 pp.
Whitford, H.N., 1911. The forests of the Philippines. Part II: the principal forest trees. Bulletin No 10. Department of the Interior, Bureau of Forestry. Bureau of Printing, Manila. 113 pp.
Whitmore, T.C. & Ng, F.S.P. (Editors), 1972-1989. Tree flora of Malaya. A manual for foresters. 2nd edition. 4 volumes. Malayan Forest Records No 26. Longman Malaysia SDN. Berhad, Kuala Lumpur & Petaling Jaya.

Nguyen Ba (general part), Nguyen Nghia Thin (general part), N. Tonanon (properties) & S. Sudo (wood anatomy)

Wrightia arborea
Wrightia laevis
Wrightia pubescens

Ba, N., Thin, N.N., Tonanon, N. & Sudo, S., 1995. Wrightia R.Br.. In: Lemmens, R.H.M.J., Soerianegara, I. and Wong, W.C. (Editors): Plant Resources of South-East Asia No 5(2): Timber trees; Minor 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:
Wrightia arborea
Wrightia laevis
Wrightia pubescens