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Turraeanthus africanus (Welw. ex C.DC.) Pellegr.

Protologue
Notul. Syst. (Paris) 2: 16, 68 (1911).
Family
Meliaceae
Chromosome number
2n = c. 280
Synonyms
Turraeanthus vignei Hutch. & Dalziel (1928).
Vernacular names
Avodire (En). Avodiré (Fr).
Origin and geographic distribution
Turraeanthus africanus is widespread, from Sierra Leone east to western Uganda, and south to DR Congo and northern Angola.
Uses
The wood (trade names: avodire, avodiré) is valued for high-quality furniture, cabinet making, decorative carpentry, moulding and panelling, musical instruments, and for sliced veneer. It is suitable for light construction, flooring, ship building, vehicle bodies, toys, novelties, boxes, crates, vats, turnery, hardboard, particle board and pulpwood for paper production. It is also used as firewood and for charcoal production.
The bark is used in traditional medicine. Bark extracts are taken or added to a bath to treat cough, fever, headache, epilepsy, filariasis, and as an abortifacient. Dried and pulverized bark with salt added is rubbed into scarifications against hernia. The bark is also used as fish poison; leaves are occasionally used for the same purpose. The seed oil is used as an abortifacient.
Production and international trade
The wood of Turraeanthus africanus is traded on the international timber market, where it fetches high prices for high-quality furniture and decorative joinery. However, since the 1960s the volumes exported are very small. Côte d’Ivoire exported about 5000 m³ of logs per year between 1960 and 1974. Ghana exported 3000 m³ of logs in 1998; but only 150 m³ in 2001.
Properties
The heartwood is creamy white to pale yellow, darkening to golden yellow upon exposure to light; it is indistinctly demarcated from the 5–6 cm wide sapwood. The grain is straight to interlocked, texture fine and even. The wood is distinctly lustrous, with a silky shine. Quartersawn surfaces often have an attractive mottled figure.
The wood is medium weight, with a density of 480–660 kg/m³ at 12% moisture content. With some care, it air dries fairly easily and rapidly, but there is a serious risk of distortion and slight risk of checking. The shrinking rates are medium, from green to oven dry 3.4–4.8% radial and 5.3–7.9% tangential. Once dry, the wood is very stable in service.
At 12% moisture content, the modulus of rupture is (69–)83–166 N/mm², modulus of elasticity 8300–12,100 N/mm², compression parallel to grain 36–61 N/mm², shear 9–16 N/mm², cleavage 13–20 N/mm, Janka side hardness 4800 N and Janka end hardness 6400 N.
The wood saws and works well with ordinary equipment and with only slight dulling effects on saw teeth and cutting edges. Tearing may occur in planing because of the presence of interlocked grain; a cutting angle of 15–20° is then recommended. The wood can be polished to an excellent finish. Splitting is common during nailing and screwing, and pre-boring is recommended. The gluing, painting and varnishing properties are all good, but the bending properties are poor. Sliced veneer of excellent quality can be produced, but the logs are often too irregular to produce good results in peeling.
The wood is not durable, being susceptible to fungal, dry-wood borer, termite and marine borer attacks. The heartwood is resistant to impregnation with preservatives, the sapwood is more permeable. The sawdust is very irritant and may even cause internal bleeding in wood workers; good ventilation is required.
Several diterpenoids and triterpenoids have been isolated from the bark and seeds. Stem bark extracts and some of the isolated diterpenoids exhibited significant antimicrobial activities against the pathogenic fungus Cryptococcus neoformans and the bacterium Staphylococcus aureus. Alkaloids have also been isolated from the stem bark. Bark extracts showed some activity against the storage pest beetles Callosobruchus maculatus and Sitophilus zeamais. A labdane diterpenoid (methyl 14,15-epoxylabda-8(17),12E-dien-16-oate) isolated from the bark exhibited in-vitro anti-plasmodial activity against a chloroquine-resistant strain of Plasmodium falciparum. The ent-labdane (+)-12,15-epoxylabda-8(17),12,14-trien-16-yl acetate isolated from the seeds showed in-vitro cytotoxic effects on cancer cell lines.
Adulterations and substitutes
The wood of Turraeanthus africanus has some resemblance to the wood of Alstonia boonei De Wild., Antiaris toxicaria Lesch., Canarium schweinfurthii Engl., Parkia bicolor A.Chev., Pterygota macrocarpa K.Schum. and Terminalia ivorensis A.Chev., and serves in Ghana as a substitute for them. In Europe it is used as a substitute for European beech (Fagus), European oak (Quercus) and sycamore (Acer).
Description
Evergreen medium-sized to fairly large tree up to 35(–45) m tall; bole branchless for up to 15(–30) m, up to 100(–120) cm in diameter, fluted or with short buttresses at base, sometimes extending in large surface roots; bark surface smooth to scaly, sometimes shallowly fissured and with vertical rows of lenticels, grey to pale brown, inner bark pale yellow to pale brown, with orange speckles and cedar-like smell; crown irregular, spreading, dark green, with ascending branches; twigs densely rusty short-hairy, glabrescent. Leaves alternate, clustered in lax groups at ends of branches, paripinnately or imparipinnately compound with (5–)8–36 leaflets; stipules absent; petiole 5–17 cm long, swollen and slightly winged at base, rachis up to 60 cm long; petiolules 5–10 mm long; leaflets alternate to opposite, oblong-elliptical to oblong-lanceolate, 6–29 cm × 2–6(–8) cm, cuneate to rounded at base, shortly acuminate at apex, tip with folded margins, leathery, initially short-hairy below but soon glabrescent, minutely scaly, pinnately veined with 10–30 pairs of lateral veins. Inflorescence an axillary panicle up to 70 cm long, often on older branches, densely rusty hairy. Flowers functionally unisexual, regular, 5-merous; pedicel c. 2 mm long, jointed at base; calyx saucer-shaped, 1–2 mm long, densely hairy; corolla tube 1.5–2 cm long, lobes 0.5–1 cm long, hairy outside, creamy white to brownish yellow; male flowers with stamens fused into a cup-shaped tube united with the corolla, with 10 included anthers, ovary not functional; female flowers with superior, conical ovary, 4–5-celled, gradually passing into the style, stigma disk-shaped, stamens not functional. Fruit a pear-shaped to nearly globose capsule 2–3.5 cm long, 2–5-lobed, orange-brown when ripe, opening near the apex, 2–5-seeded. Seeds rounded to slightly triangular, 1.5–2.5 cm long, enclosed by a white or yellow aril. Seedling with hypogeal germination; epicotyl 4–6 cm long; first leaves alternate, simple, with long-acuminate apex.
Other botanical information
Turraeanthus comprises 2–3 species and is confined to tropical Africa. It seems closely related to Guarea, which differs in usually having the staminal tube free from the corolla and in wood-anatomical characteristics.
Anatomy
Wood-anatomical description (IAWA hardwood codes):
Growth rings: 2: growth ring boundaries indistinct or absent. Vessels: 5: wood diffuse-porous; 13: simple perforation plates; 22: intervessel pits alternate; 23?: shape of alternate pits polygonal; 24: intervessel pits minute ( 4 μm); 30: vessel-ray pits with distinct borders; similar to intervessel pits in size and shape throughout the ray cell; 42: mean tangential diameter of vessel lumina 100–200 μm; 47: 5–20 vessels per square millimetre; 58: gums and other deposits in heartwood vessels. Tracheids and fibres: 61: fibres with simple to minutely bordered pits; (65: septate fibres present); 66: non-septate fibres present; 68: fibres very thin-walled; 69: fibres thin- to thick-walled. Axial parenchyma: 78: axial parenchyma scanty paratracheal; 79: axial parenchyma vasicentric; 92: four (3–4) cells per parenchyma strand; 93: eight (5–8) cells per parenchyma strand. Rays: 97: ray width 1–3 cells; 104: all ray cells procumbent; 106: body ray cells procumbent with one row of upright and/or square marginal cells; 115: 4–12 rays per mm. Mineral inclusions: 136: prismatic crystals present; 137: prismatic crystals in upright and/or square ray cells; 138: prismatic crystals in procumbent ray cells; (142: prismatic crystals in chambered axial parenchyma cells).
(E. Uetimane, H. Beeckman & P.E. Gasson)
Growth and development
Young seedlings require shade, but saplings need more light for proper development, preferring small gaps in the forest. Too much light, however, often results in low branching. In tests in Guinea, all seedlings planted in full sun had died after 2 years, whereas more than 80% of the seedlings planted in forest understorey had survived after 3 years. Growth was slow, however, with a mean height of 150 cm after 6 years.
The bole is often irregularly and poorly shaped, and low branching. In Uganda Turraeanthus africanus is an understorey tree with irregular, low-branching bole, but in West and Central Africa it may reach the upper canopy and develop a long, straight bole. In Côte d’Ivoire flowering trees may be found throughout the year, but flowering is most abundant in March to April, whereas fruits mature about 5 months later. The fruits are eaten by animals, which may disperse the seeds. However, seedlings are usually found in the close surroundings of mother trees.
Ecology
Turraeanthus africanus occurs in lowland evergreen forest and moist semi-deciduous forest, often in humid localities along streams and on the margins of poorly drained meadows and swamps. In Uganda it grows up to 1500 m altitude. For Liberia it is reported to prefer sandy soils.
Propagation and planting
Natural regeneration may be abundant near mother trees. The 1000-seed weight is about 1 kg. The viability of seeds is very short and they must be sown immediately after collection. When fresh seeds are sown the germination rate may be up to 80% in 5–7 weeks. Young seedlings require moist soil and quite deep shade. Seedlings need 10 months to reach 10 cm in height, and they have to stay in the nursery for at least one year, until the first compound leaves appear. Wildlings are occasionally collected from the forest for planting, but they are very susceptible to drought.
Management
Turraeanthus africanus usually occurs scattered and in low densities in the forest. In south-western Cameroon the average volume of boles larger than 60 cm in diameter is 0.12 m³/ha. However, in West Africa it is locally common, e.g. in Ghana, but also in Côte d’Ivoire, where in some coastal forests up to 5 trees with a bole diameter of more than 40 cm have been recorded per ha. The tree can be managed by coppicing and pollarding.
Diseases and pests
Roots of young plants in Côte d’Ivoire have been reported to be infected with the nematode Hylonema ivorense, causing necrosis of tissue which may adversely affect the growth.
Harvesting
For trees in natural forest the minimum felling diameter at breast height (dbh) is 60 cm in Côte d’Ivoire, 70 cm in Ghana and 80 cm in Liberia. Logs may have brittle heart; some caution is needed during felling operations.
Yield
With a minimum felling limit of 70 cm dbh, the annual allowable cut of Turraeanthus africanus in Ghana was estimated at 23,000 m³ in 1997.
Handling after harvest
After felling, logs should be removed immediately from the forest and rapidly converted or be treated with preservatives, because the wood is very liable to blue stain. Logs float in water and can be transported by river.
Genetic resources
Turraeanthus africanus is widespread in West and Central Africa, but it is uncommon in many regions within its distribution area. It is included in the IUCN Red list of threatened species as vulnerable because it is exploited at moderate levels for its timber and is becoming rarer in several regions where it was formerly common. However, it is still common locally in Ghana and Côte d’Ivoire. In Ghana it was rated as a ‘pink star species’, exploited at a rate of less than 50% of the sustainable cut, hence not at a rate to cause concern.
Prospects
The wood of Turraeanthus africanus is in high demand, especially for furniture and decorative veneer. The often poor shape and small size of the bole is a serious drawback, as is its very scattered occurrence in many regions. More information is needed on growth rates and ecological requirements to develop proper management strategies for sustainable exploitation in natural forest.
Major references
• ATIBT (Association Technique Internationale des Bois Tropicaux), 1986. Tropical timber atlas: Part 1 – Africa. ATIBT, Paris, France. 208 pp.
• Aubréville, A., 1959. La flore forestière de la Côte d’Ivoire. Deuxième édition révisée. Tome deuxième. Publication No 15. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 341 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.
• Burkill, H.M., 1997. The useful plants of West Tropical Africa. 2nd Edition. Volume 4, Families M–R. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 969 pp.
• CIRAD Forestry Department, 2003. Avodiré. [Internet] Tropix 5.0. http://tropix.cirad.fr/ afr/avodire.pdf. Accessed October 2007.
• Farmer, R.H., 1972. Handbook of hardwoods. 2nd Edition. Her Majesty’s Stationery Office, London, United Kingdom. 243 pp.
• Phongphaew, P., 2003. The commercial woods of Africa. Linden Publishing, Fresno, California, United States. 206 pp.
• Siepel, A., Poorter, L. & Hawthorne, W.D., 2004. Ecological profiles of large timber species. In: Poorter, L., Bongers, F., Kouamé, F.N. & Hawthorne, W.D. (Editors). Biodiversity of West African forests. An ecological atlas of woody plant species. CABI Publishing, CAB International, Wallingford, United Kingdom. pp. 391–445.
• Vivien, J. & Faure, J.J., 1985. Arbres des forêts denses d’Afrique Centrale. Agence de Coopération Culturelle et Technique, Paris, France. 565 pp.
• Voorhoeve, A.G., 1979. Liberian high forest trees. A systematic botanical study of the 75 most important or frequent high forest trees, with reference to numerous related species. Agricultural Research Reports 652, 2nd Impression. Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands. 416 pp.
Other references
• Adjanohoun, E.J., Ahyi, A.M.R., Aké Assi, L., Baniakina, J., Chibon, P., Cusset, G., Doulou, V., Enzanza, A., Eymé, J., Goudoté, E., Keita, A., Mbemba, C., Mollet, J., Moutsamboté, J.-M., Mpati, J. & Sita, P. (Editors), 1988. Médecine traditionnelle et pharmacopée - Contribution aux études ethnobotaniques et floristiques en République Populaire du Congo. Agence de Coopération Culturelle et Technique, Paris, France. 606 pp.
• African Regional Workshop (Conservation & Sustainable Management of Trees, Zimbabwe), 1998. Turraeanthus africanus. In: IUCN. 2007 IUCN Red list of threatened species. [Internet] http://www.iucnredlist.org. Accessed October 2007.
• Akam, T.M., Tane, P., Wabo, H.K., Yong, J.N., Fanso-Free, S.N.Y., Connolly, J.D., Evans, C. & Farrugia, L.J., 2006. A pregnane derivative and an anti-plasmodial labdane diterpenoid from the stem bark of Turraeanthus africanus. Natural Product Communications 1(6): 449–452.
• de Koning, J., 1983. La forêt de Banco. Part 2: La Flore. Mededelingen Landbouwhogeschool Wageningen 83–1. Wageningen, Netherlands. 921 pp.
• de la Mensbruge, G., 1966. La germination et les plantules des essences arborées de la forêt dense humide de la Côte d’Ivoire. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 389 pp.
• Hawthorne, W.D., 1995. Ecological profiles of Ghanaian forest trees. Tropical Forestry Papers 29. Oxford Forestry Institute, Department of Plant Sciences, University of Oxford, United Kingdom. 345 pp.
• InsideWood, undated. [Internet] http://insidewood.lib.ncsu.edu/search/. Accessed May 2007.
• Irvine, F.R., 1961. Woody plants of Ghana, with special reference to their uses. Oxford University Press, London, United Kingdom. 868 pp.
• Katende, A.B., Birnie, A. & Tengnäs, B., 1995. Useful trees and shrubs for Uganda: identification, propagation and management for agricultural and pastoral communities. Technical Handbook 10. Regional Soil Conservation Unit, Nairobi, Kenya. 710 pp.
• Koeppen, R.C. & Kukachka, B.F., 1961. Avodire. Turraeanthus africanus (Welw. Ex C.DC.) Pellegr. Foreign Wood Series No 1905. Forest Products Laboratory, Madison, Wisconsin, United States. 5 pp.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Normand, D. & Paquis, J., 1976. Manuel d’identification des bois commerciaux. Tome 2. Afrique guinéo-congolaise. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 335 pp.
• Oduro, S.K., 2003. Toxicity of the bark of Turraeanthus africanus on Sitophilus zeamais and Callosobruchus maculatus. B.Sc. Chemistry degree thesis, Faculty of Science, Department of Chemistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. 37 pp.
• Pauwels, L., 1993. Nzayilu N’ti: guide des arbres et arbustes de la région de Kinshasa Brazzaville. Scripta Botanica Belgica. Volume 4. Jardin botanique national de Belgique, Meise, Belgium. 495 pp.
• Pennington, T.D. & Styles, B.T., 1975. A generic monograph of the Meliaceae. Blumea 22: 419–540.
• Savill, P.S. & Fox, J.E.D., 1967. Trees of Sierra Leone. Forest Department, Freetown, Sierra Leone. 316 pp.
• Staner, P. & Gilbert, G., 1958. Meliaceae. 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 7. Institut National pour l’Étude Agronomique du Congo belge, Brussels, Belgium. pp. 147–213.
• Styles, B.T. & White, F., 1991. Meliaceae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 68 pp.
• Tatsimo, S.J., Tane, P., Srinivas, P.V., Sondengam, B.L., Melissa, J., Okunji, C.O., Schuster, B.M., Iwu, M.M. & Khan, I.A., 2005. Novel antimicrobial diterpenoids from Turraeanthus africanus. Planta Medica 71(12): 1145–1151.
• Taylor, D.P., Cadet, P. & Luc, M., 1978. An unique host-parasite relationship between Hylonema ivorense (Nematoda: Heteroderidae) and the roots of a tropical rainforest tree. Revue de Nematologie 1(1): 99–108.
• Tayman, F.S., Barku, V.Y.A., Opoku Boahen, Y., Seifert, K. & Grote, D., 2006. Isolation of ent-labdane (+)-12,15-epoxylabda-8(17),12,14-trien-16-yl acetate from the seeds of Turraeanthus africanus and its cytostatic/cytotoxic effect on the growth of cancer cells in vitro. Chemistry of Natural Compounds 42(1): 46–48.
Sources of illustration
• Voorhoeve, A.G., 1979. Liberian high forest trees. A systematic botanical study of the 75 most important or frequent high forest trees, with reference to numerous related species. Agricultural Research Reports 652, 2nd Impression. Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands. 416 pp.
• Wilks, C. & Issembé, Y., 2000. Les arbres de la Guinée Equatoriale: Guide pratique d’identification: région continentale. Projet CUREF, Bata, Guinée Equatoriale. 546 pp.
Author(s)
F.W. Owusu
Forestry Research Institute of Ghana (FORIG), University P.O. Box 63, KNUST, Kumasi, Ghana


Editors
D. Louppe
CIRAD, Département Environnements et Sociétés, Cirad es-dir, Campus international de Baillarguet, TA C-DIR / B (Bât. C, Bur. 113), 34398 Montpellier Cedex 5, France
A.A. Oteng-Amoako
Forestry Research Institute of Ghana (FORIG), University P.O. Box 63, KNUST, Kumasi, Ghana
M. Brink
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
General editors
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
J.R. Cobbinah
Forestry Research Institute of Ghana (FORIG), University P.O. Box 63, KNUST, Kumasi, Ghana
Photo editor
G.H. Schmelzer
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article:
Owusu, F.W., 2008. Turraeanthus africanus (Welw. ex C.DC.) Pellegr. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
Distribution Map wild


1, base of bole; 2, twig with leaf; 3, branch with inflorescences; 4, branch with infructescence.
Redrawn and adapted by Achmad Satiri Nurhaman



base of bole


bole


slash


slash


leaf and fruits


living room furniture


desk and chairs


wood (radial surface)


wood (tangential surface)


wood in transverse section


wood in tangential section


wood in radial section