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Antrocaryon klaineanum Pierre

Bull. Mens. Soc. Linn. Paris, n.s. 2: 24 (1898).
Vernacular names
White mahogany (En). Bouton d’antilope (Fr). Mongongo (Po).
Origin and geographic distribution
Antrocaryon klaineanum occurs from south-eastern Nigeria east to the Central African Republic and south to Gabon and DR Congo (Bas-Congo).
The wood, traded from Cameroon and Gabon as ‘onzabili’, is used for poles in construction, interior joinery, carpentry, moulding, furniture, boxes, crates, blockboard, veneer and plywood. It is suitable for light flooring, ship building, toys, novelties, carvings, hardboard, particle board and pulpwood.
The flesh of the fruit is edible with a taste like sour pears; although it is reportedly refreshing, it is not commonly consumed. The oily seeds are edible, but difficult to collect from the hard stone. In Cameroon the bark is used in traditional medicine to treat wounds, chlamydiae and female sterility, and in Congo as an emetic. In Gabon powdered bark is used to treat liver complaints and as galactagogue. Roots are used to treat abdominal and liver complaints.
Production and international trade
In 1996/1997 Cameroon exported 15,000 m³ of Antrocaryon logs, but in 1998/1999 only 2200 m³. In 2006 the average price of plywood made from Antrocaryon klaineanum was US$ 760/m³; however, the amounts exported were small. In local markets in Cameroon the price of the wood is about FCFA 55,000/m³.
Bark is sold in local markets in Cameroon for medicinal purposes. In 2000 in Yaoundé the price of 1 kg was about 4000 FCFA. The fruits are sold in local markets in Cameroon for about 10 FCFA each. They are sold on local markets in Congo for medicinal purposes.
The heartwood is pinkish white with darker streaks, darkening to pale brown upon exposure, and not distinctly demarcated from the narrow sapwood. The grain is usually straight, sometimes interlocked, texture medium to rather coarse, even. A brownish mottle figure is often present at quarter-sawn surfaces.
The wood is medium-weight to heavy with a density of (550–)620–850 kg/m³ at 12% moisture content. It usually air dries rapidly and with a slight risk of distortion and checking. The rates of shrinkage are rather high, from green to oven dry 5.6–5.8% radial and 8.5–8.6% tangential. Once dry, it is moderately stable in service.
At 12% moisture content, the modulus of rupture is 122–173 N/mm², modulus of elasticity 10,780–13,450 N/mm², compression parallel to grain 45–63 N/mm², compression perpendicular to grain 5 N/mm², shear 6.5 N/mm², cleavage 19–26 N/mm and Monnin side hardness 1.7–4.3.
The wood saws and works well, with only slight blunting effect on sawteeth and cutting edges. It planes well, but the grain may tear at surfaces. It finishes well, but the use of a filler is necessary. The nailing, screwing and gluing properties are all satisfactory. The wood peels and slices well. It is not durable, and susceptible to attacks by fungi, termites and Lyctus beetles. The heartwood is moderately resistant to treatment with preservatives, the sapwood is permeable.
Pulping tests gave satisfactory results for paper production. The wood contains about 45% cellulose, 21% lignin, 18% pentosan and 1.8% starch. The solubility is 3.0% in alcohol-benzene, 10.2% in hot water and 19.9% in a 1% NaOH solution.
Adulterations and substitutes
The wood of Antrocaryon spp. resembles that of okoumé (Aucoumea klaineana Pierre) and ilomba (Pycnanthus angolensis (Welw.) Warb.), which are both commonly used for veneer and plywood.
Evergreen or briefly deciduous, dioecious, medium-sized tree up to 35(–45) m tall; bole branchless for up to 30 m, straight and cylindrical, up to 150(–180) cm in diameter, usually without buttresses; bark surface pale grey to dark grey, longitudinally fissured and with rectangular scales, with lenticels, inner bark brittle, fibrous, orange-yellow to pinkish, with a smell of turpentine; crown hemispherical; twigs thick, angular. Leaves arranged spirally, clustered near ends of branches, imparipinnately compound with 5–8 pairs of leaflets; stipules absent; petiole and rachis together 20–40(–50) cm long, reddish, hairy; petiolules 2–3 mm long, grooved; leaflets opposite, narrowly ovate to oblong-lanceolate or oblong-elliptical, 6–16 cm × 2.5–4.5 cm, rounded to slightly cordate and asymmetrical at base, acuminate at apex, papery, glabrous except sometimes the veins beneath, pinnately veined with 10–14 pairs of lateral veins. Inflorescence an axillary lax panicle up to 30 cm long with branches up to 13 cm long, hairy. Flowers unisexual, regular, 5-merous; pedicel 1–3 mm long, jointed; calyx with lobes c. 1 mm long, slightly fused at base, short-hairy; petals free, oblong-ovate, 1.5–2 mm long, reflexed, short-hairy, yellowish white; stamens 10, c. 1.5 mm long; disk thick and slightly lobed; ovary superior, depressed-globose, 1–2 mm in diameter, glabrous, 5-celled, styles 5, short; male flowers with rudimentary ovary, female flowers slightly larger and with rudimentary stamens. Fruit a depressed-globose drupe 1.5–2 cm × 2.5–3.5 cm, yellow when ripe; stone slightly 5(–6)-lobed, 1–1.5 cm × 2–2.5 cm, with 5 apical cavities, 3–4-seeded. Seeds flattened and curved, c. 1 cm long. Seedling with epigeal germination; cotyledons oblong, thick and fleshy; first 2 leaves opposite, imparipinnately compound.
Other botanical information
Antrocaryon comprises 3 species and occurs from Sierra Leone east to Uganda.
Wood-anatomical description (IAWA hardwood codes):
Growth rings: 1: growth ring boundaries distinct. Vessels: 5: wood diffuse-porous; 13: simple perforation plates; 22: intervessel pits alternate; 23: shape of alternate pits polygonal; 27: intervessel pits large ( 10 μm); 31: vessel-ray pits with much reduced borders to apparently simple: pits rounded or angular; 42: mean tangential diameter of vessel lumina 100–200 μm; (43: mean tangential diameter of vessel lumina 200 μm); 46: 5 vessels per square millimetre; 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; (68: fibres very thin-walled); 69: fibres thin- to thick-walled. Axial parenchyma: (75: axial parenchyma absent or extremely rare); 78: axial parenchyma scanty paratracheal; 92: four (3–4) cells per parenchyma strand; 93: eight (5–8) cells per parenchyma strand; (94: over eight cells per parenchyma strand). Rays: 97: ray width 1–3 cells; (100: rays with multiseriate portion(s) as wide as uniseriate portions); 106: body ray cells procumbent with one row of upright and/or square marginal cells; 107: body ray cells procumbent with mostly 2–4 rows of upright and/or square marginal cells; 115: 4–12 rays per mm. Secretory elements and cambial variants: 130: radial canals. Mineral inclusions: (136: prismatic crystals present); (137: prismatic crystals in upright and/or square ray cells).
(N.P. Mollel, H. Beeckman & P. Baas)
Growth and development
Seedlings prefer full sunlight. In tests in Gabon, seedlings reached a height of 25–40 cm one year after germination, 65–85 cm after two years and 110–125 cm after three years. However, seedlings may reach 120 cm tall 16 months after germination. In Gabon the fruits are ripe from March to August. Trees may fruit each year. The fruits are eaten by monkeys, chimpanzees, gorillas, antelopes and rodents. They are an important food for all these animal species because they are usually available by the middle of the dry season when few other fruits are found. Larger animals serve as dispersers of the stones because they swallow whole fruits. Antelopes have been suggested as main dispersers. The base of the bole is often damaged by elephants, which eat the bark.
Antrocaryon klaineanum occurs in lowland rainforest below 1000 m altitude, most commonly in humid evergreen forest in regions with a mean annual rainfall of approximately 1500 mm. It is commonly found in secondary forest. It has been reported to grow on sandy and sandy-clay soils, sometimes on ferralitic soils.
Propagation and planting
Stones normally germinate within one month, rarely after 2 months. However, germination after 1–2 years has also been reported. The germination rate is about 25%. Up to 3 seedlings may develop from one stone. In experiments in Gabon, seedlings did not survive transplanting and propagation by cuttings was not successful with only one of 23 cuttings developing new shoots.
In forest in south-western Cameroon, the average number of Antrocaryon boles over 60 cm in diameter is 0.08 per ha, with an average wood volume of 0.6 per ha. Antrocaryon klaineanum is not cultivated, but in agroforestry systems with cacao in southern Cameroon, an average density of 0.4 tree per ha can be found. In Cameroon the minimum bole diameter for harvesting is 50 cm.
The fruits are usually collected from the ground.
A bole of 20 m long and 100 cm in diameter produces about 11 m³ of timber.
Handling after harvest
Logs should be removed from the forest immediately after felling for processing, or they should be treated with preservatives, because they are susceptible to blue stain attack.
Genetic resources
In general, larger trees of Antrocaryon klaineanum occur scattered in the forest and are uncommon. The dispersal of the seeds is dependent on large mammals such as antelopes, chimpanzees and gorillas, and research in Cameroon showed that intense hunting pressure in the forest seriously reduces the dissemination of Antrocaryon klaineanum. The species is often found in secondary forest and does not seem to be threatened at present, but some monitoring of populations is needed, especially in Cameroon where it seems to be most widespread.
Although Antrocaryon klaineanum has been classified in Cameroon as a promising timber species (second category), little information is available. Research on growth rates and propagation methods is needed before it can be seriously considered as a commercial timber producer on a sustainable basis.
Major references
• ATIBT (Association Technique Internationale des Bois Tropicaux), 1986. Tropical timber atlas: Part 1 – Africa. ATIBT, Paris, France. 208 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.
• Bourobou-Bourobou, H., 1994. Biologie et domestication de quelques arbres fruitiers de la forêt du Gabon. Thèse Université Montpellier II - Sciences et Techniques du Languedoc, Montpellier, France. 340 pp.
• CIRAD Forestry Department, 2009. Onzabili. [Internet] Tropix 6.0. africa/onzabili.pdf. Accessed March 2010.
• de Saint-Aubin, G., 1963. La forêt du Gabon. Publication No 21 du Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 208 pp.
• Takahashi, A., 1978. Compilation of data on the mechanical properties of foreign woods (part 3) Africa. Shimane University, Matsue, Japan. 248 pp.
• van der Veken, P., 1960. Anacardiaceae. 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 9. Institut National pour l’Étude Agronomique du Congo belge, Brussels, Belgium. pp. 5–108.
• Vivien, J. & Faure, J.J., 1985. Arbres des forêts denses d’Afrique Centrale. Agence de Coopération Culturelle et Technique, Paris, France. 565 pp.
• Wang, B.C., Sork, V.L., Leong, M.T. & Smith, T.B., 2007. Hunting of mammals reduces seed removal and dispersal of the afrotropical tree Antrocaryon klaineanum (Anacardiaceae). Biotropica 39(3): 340–347.
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.
• Betti, J.L., 2002. Medicinal plants sold in Yaoundé markets, Cameroon. African Study Monographs 23(2): 47–64.
• Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 960 pp.
• Chaudron, A., 2000. Cameroun: l’arrêt des exportations de grumes. Canopée 16: 14–16.
• Fougerousse, M., 1970. Durabilité des panneaux contreplaqués en bois feuillus tropicaux. Bois et Forêts des Tropiques 134: 63–69.
• Gassita, J.N., Nze Ekekang, L., De Vecchy, H., Louis, A.M., Koudogbo, B. & Ekomié, R. (Editors), 1982. Les plantes médicinales du Gabon. CENAREST, IPHAMETRA, mission ethnobotanique de l’ACCT au Gabon, 10–31 juillet 1982. 26 pp.
• Keay, R.W.J., 1989. Trees of Nigeria. A revised version of Nigerian trees (1960, 1964) by Keay, R.W.J., Onochie, C.F.A. & Stanfield, D.P. Clarendon Press, Oxford, United Kingdom. 476 pp.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Nkeoua, G. & Boundzanga, G.C., 1999. Données sur les produits forestières non ligneux en République du Congo. FAO, Brazzaville, Congo. 125 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.
• Raponda-Walker, A. & Sillans, R., 1961. Les plantes utiles du Gabon. Paul Lechevalier, Paris, France. 614 pp.
• Tailfer, Y., 1989. La forêt dense d’Afrique centrale. Identification pratique des principaux arbres. Tome 2. CTA, Wageningen, Pays Bas. pp. 465–1271.
• Vivien, J. & Faure, J.J., 1996. Fruitiers sauvages d’Afrique: espèces du Cameroun. Ministère Français de la Coopération, Paris, France & CTA, Wageningen, Netherlands. 416 pp.
• White, L. & Abernethy, K., 1997. A guide to the vegetation of the Lopé Reserve, Gabon. 2nd edition. Wildlife Conservation Society, New York, United States. 224 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.
Sources of illustration
• 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.
• Wilks, C. & Issembé, Y., 2000. Les arbres de la Guinée Equatoriale: Guide pratique d’identification: région continentale. Projet CUREF, Bata, Guinée Equatoriale. 546 pp.
V.A. Kémeuzé
Millennium Ecologic Museum, B.P. 8038, Yaoundé, Cameroon
B.A. Nkongmeneck
Millennium Ecologic Museum, B.P. 8038, Yaoundé, Cameroon

R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
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
Associate editors
E.A. Obeng
Forestry Research Institute of Ghana (FORIG), University P.O. Box 63, KNUST, Kumasi, Ghana

Correct citation of this article:
Kémeuzé, V.A. & Nkongmeneck, B.A., 2011. Antrocaryon klaineanum Pierre. In: Lemmens, R.H.M.J., Louppe, D. & Oteng-Amoako, A.A. (Editors). Prota 7(2): Timbers/Bois d’œuvre 2. [CD-Rom]. PROTA, Wageningen, Netherlands.
Distribution Map wild

1, base of bole; 2, part of flowering branch; 3, fruits; 4, stones.
Redrawn and adapted by Isaac Ossei Agyekumhene