Ocotea kenyensis (PROTA)

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Plant Resources of Tropical Africa
Introduction
List of species


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distribution in Africa (wild)
1, tree habit; 2, flowering twig; 3, fruiting twig. Redrawn and adapted by Iskak Syamsudin
flush (Zimbabweflora)
leaf lower surface (Zimbabweflora)
wood in transverse section
wood in tangential section
wood in radial section

Ocotea kenyensis (Chiov.) Robyns & R.Wilczek


Protologue: Bull. Jard. Bot. Etat 20: 212 (1950).
Family: Lauraceae

Synonyms

  • Ocotea viridis Kosterm. (1938).

Vernacular names

  • Bastard stinkwood, northern stinkwood, Transvaal stinkwood (En).

Origin and geographic distribution

Ocotea kenyensis occurs from southern Sudan and southern Ethiopia, through eastern DR Congo, Rwanda, Kenya, Uganda and Tanzania, to Zimbabwe, Mozambique, Swaziland and eastern South Africa.

Uses

The wood is used for flooring, panelling, furniture and carving. It is suitable for light construction, joinery, interior trim, vehicle bodies, handles, ladders, sporting goods, toys, novelties, turnery, veneer and plywood. It is also used as firewood and for charcoal production.

A bark decoction is used in traditional medicine as an antitussive. The bark is chewed to treat diarrhoea.

Properties

The heartwood is pale golden brown to dark brown, with blackish markings; it is lustrous. The grain is often wavy, texture moderately fine. The wood is moderately heavy, with a density of about 750 kg/m³ at 12% moisture content. It air dries slowly and should be dried with care to avoid serious degrade. Drying of thick boards may be problematic. The rates of shrinkage are moderately high.

The wood saws and works satisfactory with both hand and machine tools, but picking up of grain at the surfaces may occur; sharp cutting edges are recommended to obtain surfaces with a nice finish. The gluing properties are satisfactory. The wood slices and peels well. It is fairly durable and moderately resistant to termite and marine borer attacks, but susceptible to Lyctus attack. The heartwood is moderately resistant to impregnation by preservatives.

Description

  • Evergreen, small to medium-sized tree up to 30(–40) m tall; bole usually straight, up to 100(–150) cm in diameter; bark surface greyish brown to reddish brown, rough, scaling off in irregular flakes, with conspicuous, scattered lenticels, inner bark greenish white to yellowish brown or orange, turning dark grey to dark brown upon exposure; crown rounded, much-branched, dark green; branches with distinct leaf scars, twigs angular, short-hairy to nearly glabrous.
  • Leaves alternate, simple; stipules absent; petiole 0.5–1.5(–2) cm long; blade ovate to elliptical, (4.5–)6.5–22 cm × 2–10 cm, cuneate to rounded at base, acute to acuminate at apex, margins entire or wavy, leathery, glossy dark green above, paler below, often reddish at margins, red when young, glabrous, pinnately veined with 8–10 pairs of lateral veins, with aromatic scent.
  • Inflorescence an axillary or terminal cyme or panicle up to 7 cm long, densely greyish short-hairy, few-flowered; peduncle 0.5–1(–2.5) cm long.
  • Flowers bisexual or unisexual, regular, fragrant; pedicel 1–5 mm long, thickening in fruit; perianth lobes 6, ovate-elliptical to orbicular or obovate, 2–3.5 mm long, greenish yellow or whitish yellow, short-hairy; stamens (7–)9 in 3 whorls, anthers 4-celled, stamens of inner whorl with 2 glands at base, staminodes forming a fourth whorl around the ovary or absent; ovary superior, ovoid to globose, c. 1 mm long, glabrous, 1-celled, style 1–1.5 mm long, stigma disk-shaped; male flowers with reduced ovary, female flowers with reduced stamens.
  • Fruit an oblong-ellipsoid to ovoid-ellipsoid drupe-like berry 1.5–2.5 cm long, olive-green, at base enclosed in the cup-like enlarged receptacle c. 1 cm long, 1-seeded.

Other botanical information

The estimated number of species in Ocotea ranges from 200 to 350 species, most of them in tropical America. Mainland Africa has about 7 species, Madagascar about 35.

Ocotea bullata

Ocotea bullata (Burch.) Baill. is endemic to eastern and southern South Africa. It strongly resembles Ocotea kenyensis, but differs in its leaves having blisters in the axils of the lower lateral veins. Its yellowish grey to dark brown, often nicely figured and lustrous wood, known as ‘stinkwood’, is already for centuries in high demand, especially for furniture, small ornaments and turnery, and is highly prized. Methods of sustainable production of timber have been developed recently, which, however, allow only very little production. The wood is also used as firewood. The bark is important in traditional medicine, particularly to treat headache, urinary and nervous disorders, stomach complaints and diarrhoea. Ocotea bullata is planted as ornamental tree in gardens and parks.

Anatomy

Wood-anatomical description (IAWA hardwood codes):

  • Growth rings: (1: growth ring boundaries distinct); (2: growth ring boundaries indistinct or absent).
  • Vessels: 5: wood diffuse-porous; (11: vessel clusters common); 12: solitary vessel outline angular; 13: simple perforation plates; (14: scalariform perforation plates); (15: scalariform perforation plates with 10 bars); 22: intervessel pits alternate; 23: shape of alternate pits polygonal; 25: intervessel pits small (4–7 μm); 31: vessel-ray pits with much reduced borders to apparently simple: pits rounded or angular; 32: vessel-ray pits with much reduced borders to apparently simple: pits horizontal (scalariform, gash-like) to vertical (palisade); 42: mean tangential diameter of vessel lumina 100–200 μm; 47: 5–20 vessels per square millimetre; (56: tyloses common).
  • Tracheids and fibres: 61: fibres with simple to minutely bordered pits; 65: septate fibres present; 66: non-septate fibres present; 69: fibres thin- to thick-walled.
  • Axial parenchyma: 78: axial parenchyma scanty paratracheal; 93: eight (5–8) cells per parenchyma strand.
  • Rays: 97: ray width 1–3 cells; 106: body ray cells procumbent with one row of upright and/or square marginal cells; 115: 4–12 rays per mm.
  • Secretory elements and cambial variants: 124: oil and/or mucilage cells associated with ray parenchyma; 125: oil and/or mucilage cells associated with axial parenchyma.
(P. Ng’andwe, H. Beeckman & P.E. Gasson)

Growth and development

In general, the tree grows fairly rapidly. The fruits are eaten by birds, which may serve as seed dispersers.

Ecology

Ocotea kenyensis occurs in evergreen rainforest at 1100–2400(–2600) m altitude. The mean annual rainfall in the area of distribution ranges from 1500 mm to 2200 mm. In the mountains of southern Sudan it occurs together with Podocarpus and Albizia spp., and in Kenya with Podocarpus and Macaranga spp.

Propagation and planting

Fresh seed should be used for sowing. Seed is sensitive to desiccation, but can be stored for a short period in moist saw dust.

Propagation by root suckers is easy; these are often produced abundantly. Under natural conditions, regeneration of Ocotea kenyensis by seed in Ethiopia was found to be satisfactory.

Management

Ocotea kenyensis trees can be managed by coppicing.

Diseases and pests

Fruits are often heavily attacked by insects.

Genetic resources

In many regions Ocotea kenyensis has been heavily exploited for its valuable timber. In southern Africa it shows a very scattered distribution pattern, with often only small groups of trees or individual trees geographically isolated from other stands. It is critically endangered in Zimbabwe. Ocotea kenyensis is included in the IUCN Red list as vulnerable.

Prospects

Although Ocotea kenyensis provides valuable timber and has been over-exploited, very little research has been done on its wood properties, growth rates and propagation methods. The findings of such research are needed to be able to develop methods of sustainable exploitation. This would probably result in very low production levels, but the example of Ocotea bullata in South Africa shows that this might still be a valuable option for such high-quality timbers.

Major references

  • Bekele-Tesemma, A., 2007. Useful trees and shrubs for Ethiopia: identification, propagation and management for 17 agroclimatic zones. Technical Manual No 6. RELMA in ICRAF Project, Nairobi, Kenya. 552 pp.
  • Bolza, E. & Keating, W.G., 1972. African timbers: the properties, uses and characteristics of 700 species. Division of Building Research, CSIRO, Melbourne, Australia. 710 pp.
  • Diniz, M.A., 1997. Lauraceae. In: Pope, G.V. (Editor). Flora Zambesiaca. Volume 9, part 2. Royal Botanic Gardens, Kew, Richmond, United Kingdom. pp. 45–59.
  • Friis, I., 1992. Forests and forest trees of northeast tropical Africa: their natural habitats and distribution patterns in Ethiopia, Djibouti and Somalia. Kew Bulletin, Additional Series 15, H.M.S.O., London, United Kingdom. 396 pp.
  • Maundu, P. & Tengnäs, B. (Editors), 2005. Useful trees and shrubs for Kenya. World Agroforestry Centre - East and Central Africa Regional Programme (ICRAF-ECA), Technical Handbook 35, Nairobi, Kenya. 484 pp.
  • Palmer, E. & Pitman, N., 1972–1974. Trees of southern Africa, covering all known indigenous species in the Republic of South Africa, South-West Africa, Botswana, Lesotho and Swaziland. 3 volumes. Balkema, Cape Town, South Africa. 2235 pp.
  • Sommerlatte, H. & Sommerlatte, M., 1990. A field guide to the trees and shrubs of the Imatong Mountains, southern Sudan. Deutsche Gesellschaft fur Technische Zusammmenarbeit (GTZ), Nairobi, Kenya. 372 pp.
  • Strahm, W., 1998. Canarium paniculatum. In: IUCN. 2007 Red list of threatened species. [Internet] http://www.iucnredlist.org. January 2008.

Other references

  • Beentje, H.J., 1994. Kenya trees, shrubs and lianas. National Museums of Kenya, Nairobi, Kenya. 722 pp.
  • Bekele-Tesemma, A., Birnie, A. & Tengnäs, B., 1993. Useful trees and shrubs for Ethiopia: identification, propagation and management for agricultural and pastoral communities. Technical Handbook No 5. Regional Soil Conservation Unit/SIDA, Nairobi, Kenya. 474 pp.
  • Coates Palgrave, K., 1983. Trees of southern Africa. 2nd Edition. Struik Publishers, Cape Town, South Africa. 959 pp.
  • Dale, I.R. & Greenway, P.J., 1961. Kenya trees and shrubs. Buchanan’s Kenya Estates Limited, Nairobi, Kenya. 654 pp.
  • Friis, I., 2000. Lauraceae. In: Edwards, S., Mesfin Tadesse, Demissew Sebsebe & Hedberg, I. (Editors). Flora of Ethiopia and Eritrea. Volume 2, part 1. Magnoliaceae to Flacourtiaceae. The National Herbarium, Addis Ababa University, Addis Ababa, Ethiopia and Department of Systematic Botany, Uppsala University, Uppsala, Sweden. pp. 14–17.
  • Hamill, F.A., Apio, S., Mubiru, N.K., Mosango, M., Bukenya-Ziraba, R., Maganyi, O.W. & Soejarto, D.D., 2000. Traditional herbal drugs of southern Uganda, 1. Journal of Ethnopharmacology 70: 281–300.
  • Robyns, W. & Wilczek, R., 1951. Lauraceae. In: Robyns, W., Staner, P., Demaret, F., Germain, R., Gilbert, G., Hauman, L., Homès, M., Jurion, F., Lebrun, J., Vanden Abeele, M. & Boutique, R. (Editors). Flore du Congo belge et du Ruanda-Urundi. Spermatophytes. Volume 2. Institut National pour l’Étude Agronomique du Congo belge, Brussels, Belgium. pp. 403–446.
  • Troupin, G., 1982. Flore des plantes ligneuses du Rwanda. Publication No 21. Institut National de Recherche Scientifique, Butare, Rwanda. 747 pp.
  • van Wyk, B.E. & Gericke, N., 2000. People’s plants: a guide to useful plants of southern Africa. Briza Publications, Pretoria, South Africa. 351 pp.
  • Verdcourt, B., 1996. Lauraceae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 19 pp.
  • Wimbush, S.H., 1957. Catalogue of Kenya timbers. 2nd reprint. Government Printer, Nairobi, Kenya. 74 pp.

Sources of illustration

  • Hutchinson, J. & Moss, M.B., 1930. A new stinkwood from East Africa. Bulletin of Miscellaneous Information Kew 1930: 68–70.
  • Maundu, P. & Tengnäs, B. (Editors), 2005. Useful trees and shrubs for Kenya. World Agroforestry Centre - East and Central Africa Regional Programme (ICRAF-ECA), Technical Handbook 35, Nairobi, Kenya. 484 pp.
  • Palmer, E. & Pitman, N., 1972–1974. Trees of southern Africa, covering all known indigenous species in the Republic of South Africa, South-West Africa, Botswana, Lesotho and Swaziland. 3 volumes. Balkema, Cape Town, South Africa. 2235 pp.

Author(s)

  • F.S. Mairura, Kenya Tropical Soil Biology and Fertility Institute of CIAT, P.O. Box 30677, Nairobi, Kenya
  • R.H.M.J. Lemmens, PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article

Mairura, F.S. & Lemmens, R.H.M.J., 2008. Ocotea kenyensis (Chiov.) Robyns & R.Wilczek. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. Accessed 25 April 2019.