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Celtis africana Burm.f.

Protologue
Fl. indica: 31 (1768).
Family
Celtidaceae (APG: Cannabaceae)
Chromosome number
2n = 20
Synonyms
Celtis kraussiana Bernh. (1845).
Vernacular names
White stinkwood, Camdeboo stinkwood (En).
Origin and geographic distribution
Celtis africana is widespread in tropical Africa, occurring from Ghana eastwards to Somalia and south to South Africa and Lesotho. It is also found in Yemen.
Uses
The wood (trade name ‘celtis’) is used for construction, flooring, joinery, interior trim, mine props, furniture, ladders, toys, novelties, sporting goods, agricultural implements, tool handles, pestles, tent-bows, yokes, wagon-making, spoons, boxes and crates. It is suitable for ship building, railway sleepers, veneer and plywood. It is also used as firewood and for charcoal production.
Several plant parts are used in traditional medicine. In Nigeria pounded bark is used to treat fever, headache and general malaise. A leaf decoction is applied to sore eyes. In Lesotho unspecified plant parts are used to treat pleurisy. The leaves serve as fodder for livestock; they are often fed to goats to relief them of indigestion. In Lesotho the fibrous bark is commonly used for making ropes, in Congo for clothes. The tree is commonly planted as ornamental shade tree and roadside tree.
Production and international trade
The wood of Celtis africana is rarely traded on the international market and is mostly used locally.
Properties
The heartwood is yellowish white or pale brown to greenish brown, occasionally with dark irregular streaks, and not distinctly demarcated from the whitish sapwood. There is often a dark brown to black stain around the pith. The grain is usually straight, sometimes interlocked, texture fine to moderately coarse and even. Freshly cut wood has an unpleasant smell, which has sometimes been described as ‘apple-like’.
The wood is moderately heavy with a density of (640–)710–770(–820) kg/m³ at 12% moisture content, and moderately hard. It dries fairly well with moderate degrade, but checking and end splitting may occur. Close stacking in air drying is recommended. The rates of shrinkage are moderate, from green to 12% moisture content 1.9–3.0% radial and 3.4–5.9% tangential, and from green to oven dry about 4.4% radial and 7.9% tangential. Once dry, the wood is stable in service.
At 12% moisture content, the modulus of rupture is 103–130 N/mm², modulus of elasticity 11, 950–16,400 N/mm², compression parallel to grain 53–71 N/mm², shear 12–17 N/mm², Janka side hardness 7340–7750 N and Janka end hardness 8660–9340 N.
The wood is fairly easy to saw and work with both machine and hand tools, and has moderate blunting effect on cutting edges. In planing a reduced cutting angle is needed to avoid tearing at surfaces. The wood takes a good finish with nice polish without the use of a filler. It has good nailing properties, but with some tendency to splitting. It glues well. Boring and mortising should be done with good support. The bending properties are excellent, but turning properties poor. The wood peels well. It has a low durability and is susceptible to attacks by blue-stain fungi, termites, Lyctus and marine borers. The heartwood is moderately resistant to impregnation with preservatives, but the sapwood is permeable; however, both can be treated well under pressure.
Methanol extracts from leaves and stems showed significant antioxidant activity, which is likely due to the presence of polyphenolic compounds. Root and leaf extracts showed only slight or no activity on cestodes of the tapeworm Hymenolepis diminuta after one hour, but significant activity after 24 hours. The bark has a high content of phenolic compounds, deterring porcupines from damaging the bark. The pollen has been recorded as an allergen.
Adulterations and substitutes
At the beginning of the 20th century Celtis africana wood has been used as a substitute of ash, hickory and oak with some success.
Description
Deciduous shrub or small to medium-sized tree up to 30(–40) m tall; bole usually straight, cylindrical, branchless for up to 15 m but often low-branching, up to 90 cm in diameter, often slightly fluted, usually without buttresses; bark surface smooth, whitish grey, often pinkish blotched, inner bark greyish with brown blotches, rapidly becoming dark brown upon exposure; crown rounded, dark green, with branches drooping towards tips; twigs densely yellowish brown short-hairy. Leaves alternate, simple; stipules linear, 3–8 mm long, hairy, caducous; petiole up to 0.5(–1) cm long, slightly grooved above; blade ovate to ovate-lanceolate, 3–10 cm × 2.5–6 cm, cuneate to rounded and very asymmetrical at base, with acuminate apex, margins coarsely toothed, papery, slightly hairy below especially on veins, rough above, prominently 3-veined from the base and additionally with 1–2 pairs of lateral veins. Inflorescence an axillary cyme up to 2.5 cm long, densely short-hairy. Flowers unisexual or bisexual, regular, 4–5-merous, small, white to greenish; tepals 1.5–2.5 mm long, hairy; stamens free, c. 1.5 mm long; ovary superior, ovoid, densely hairy, 1-celled, styles 2, unbranched; male flowers 3–many together in lower leaf axils, with pedicel 1.5–5 mm long and rudimentary ovary; female flowers and/or bisexual flowers 1–few together in upper leaf axils, with pedicel 10–17 mm long, female flowers with rudimentary stamens. Fruit an ellipsoid to globose drupe 4–8 mm long, pointed, orange when ripe, short-hairy; stone ovoid to globose, c. 4 mm long, slightly pitted, grey, 1-seeded. Seedling with epigeal germination.
Other botanical information
Celtis comprises about 100 species and is widespread in all tropical, subtropical and temperate regions. For tropical Africa 11 species have been recorded, 2 of which are endemic to Madagascar. Celtis is taxonomically a difficult genus, showing much morphological variability. Traditionally, it has been treated as part of the family Ulmaceae, but later it was often considered to belong to a separate family Celtidaceae, whereas from most recent research it was proposed to take up the latter family into Cannabaceae.
Growth and development
Celtis africana grows fast, 1–2 m per year. First fruits may appear when trees are 4 years old. Flowering trees have been recorded from August to October in southern Africa, and in May in Ghana. The flowers are usually pollinated by insects such as bees. Fruits ripen about 2 months after flowering. They are relished by birds such as bulbuls, mousebirds and barbets, they are an important component of the diet of colobus monkeys, and are also eaten by baboons. All these animals may contribute to seed dispersal.
Ecology
Celtis africana occurs in a very wide range of habitats, from savanna to dry evergreen forest, riverine forest, montane rainforest and coastal forest, from sea-level up to 2400 m altitude. In Somalia it is typical of evergreen Juniperus and Buxus forest at altitudes of 1650–2000 m. Although it prefers relatively fertile and deep moist soils, it can also be found on sandy dunes and river banks, as well as on rocky soils, but under these conditions it usually only develops into a shrub. It is moderately drought resistant and can withstand light frost. In South Africa trees have been recorded to be severely affected by water logging conditions, leading to death of trees.
Propagation and planting
In Uganda it has been recorded that Celtis africana does not regenerate under the canopy. In gaps regeneration was prolific. Celtis africana is propagated by seed and wildlings. The 1000-seed weight is 40–60 g. Seeds collected from the ground are mostly infested by insects, and it is recommended to harvest fruits directly from the trees when they turn from yellowish to brownish, and to dry them in the sun before extracting stones. These should be cleaned from fruit flesh before sowing. Fresh seeds germinate within 60 days and may have a high germination rate. Treatment is not necessary, but germination is hastened by soaking stones in cold water for 24 hours before sowing. They can be stored for some time in airtight containers. In South Africa seeds are sown in flat seedling trays filled with a mixture of 5 parts river sand and 1 part well decomposed compost placed in a warm but shaded place. To promote germination, seeds should be covered with a thin layer of river sand and kept moist; under these circumstances germination takes 15–30 days with a germination rate up to 70%. It is recommended to transplant seedlings into fertile soil. They should be watered sparingly.
Management
Celtis africana is easy to grow under a wide range of conditions. Trees can be managed by side pruning.
Diseases and pests
Fruits are heavily attacked by insects. Celtis africana is a host plant for the butterfly Libythea labdaca, the caterpillars feeding on the leaves.
Genetic resources
Celtis africana is widespread and locally common, and does not appear to be liable to genetic erosion. Moreover, in South Africa it is commonly planted as an ornamental tree in gardens.
Prospects
Celtis africana is a multipurpose tree valued for its timber, firewood and forage, and as ornamental and medicinal plant. It has potential to serve as substitute for other Celtis species that are more commonly traded on the international timber market, such as Celtis mildbraedii Engl. and Celtis zenkeri Engl. Little research has so far been done on Celtis africana and research on its growth rates, propagation methods and management requirements is therefore warranted. Research is needed to confirm its suitability for plywood production.
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.
• Burkill, H.M., 2000. The useful plants of West Tropical Africa. 2nd Edition. Volume 5, Families S–Z, Addenda. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 686 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.
• Fici, S., 1999. Ulmaceae (incl. Celtidaceae). In: Thulin, M. (Editor). Flora of Somalia. Volume 2. Angiospermae (Tiliaceae-Apiaceae). Royal Botanic Gardens, Kew, Richmond, United Kingdom. pp. 88–91.
• Letouzey, R., 1968. Ulmaceae. Flore du Cameroun. Volume 8. Muséum National d’Histoire Naturelle, Paris, France. pp. 3–65.
• Mbambezeli, G. & Notten, A., 2008. Celtis africana Burm.f. [Internet] South African National Biodiversity Institute, Kirstenbosch, South Africa. http://www.plantzafrica.com/ plantcd/ celtisafrican.htm. Accessed November 2009.
• Polhill, R.M., 1966. Ulmaceae. In: Hubbard, O.B.E. & Milne-Redhead, E. (Editors). Flora of Tropical East Africa. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. 15 pp.
• Wilmot-Dear, C.M., 1999. FSA contributions 13: Ulmaceae. Bothalia 29(2): 239–247.
Other references
• Adedapo, A.A., Jimoh, F.O., Koduru, S., Afolayan, A.J. & Masika, P.J., 2009. Antioxidant properties of the methanol extracts of the leaves and stems of Celtis africana. Records of Natural Products 3(1): 23–31.
• Aggarwal, S., 1998. Celtis L. In: Sosef, M.S.M., Hong, L.T. & Prawirohatmodjo, S. (Editors). Plant Resources of South-East Asia No 5(3). Timber trees: Lesser-known timbers. Backhuys Publishers, Leiden, Netherlands. pp. 150–153.
• Beentje, H.J., 1994. Kenya trees, shrubs and lianas. National Museums of Kenya, Nairobi, Kenya. 722 pp.
• Bryce, J.M., 1967. The commercial timbers of Tanzania. Tanzania Forest Division, Utilisation Section, Moshi, Tanzania. 139 pp.
• Chikamai, B.N., Githiomi, J.K., Gachathi, F.N. & Njenga, M.G., undated. Commercial timber resources of Kenya. Kenya Forestry Research Institute (KEFRI), Nairobi, Kenya. 164 pp.
• Irvine, F.R., 1961. Woody plants of Ghana, with special reference to their uses. Oxford University Press, London, United Kingdom. 868 pp.
• Johnson, D. & Johnson, S., 2002. Down to Earth: Gardening with indigenous trees. Struik Publishers, Cape Town, South Africa. 112 pp.
• Kasenene, J.M., 1998. Forest association and phenology of wild coffee in Kibale National Park, Uganda. African Journal of Ecology 36: 241–250.
• 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.
• Kokwaro, J.O., 1993. Medicinal plants of East Africa. 2nd Edition. Kenya Literature Bureau, Nairobi, Kenya. 401 pp.
• Liu, K., Eastwood, R.J., Flynn, S., Turner, R.M. & Stuppy, W.H., 2008. Seed Information Database Release 7.1, May 2008. [Internet] http://data.kew.org/ sid/. Accessed November 2009.
• 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.
• Mølgaard, P., Nielsen, S.B., Rasmussen, D.E., Drummond, R.B., Makaza, N. & Andreassen, J., 2001. Anthelmintic screening of Zimbabwean plants traditionally used against schistosomiasis. Journal of Ethnopharmacology 74: 257–264.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 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.
• Sattarian, A., 2006. Contribution to the biosystematics of Celtis L. (Celtidaceae) with special emphasis on the African species. PhD thesis. Wageningen University, Wageningen, Netherlands. 142 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.
• Widodo, S.H., 2001. Crescentia L. In: van Valkenburg, J.L.C.H. & Bunyapraphatsara, N. (Editors). Plant Resources of South-East Asia No 12(2): Medicinal and poisonous plants 2. Backhuys Publishers, Leiden, Netherlands. pp. 191–194.
• Wilmot-Dear, C.M., 1991. Ulmaceae. In: Launert, E. & Pope, G.V. (Editors). Flora Zambesiaca. Volume 9, part 6. Flora Zambesiaca Managing Committee, London, United Kingdom. pp. 1–10.
• Wimbush, S.H., 1957. Catalogue of Kenya timbers. 2nd reprint. Government Printer, Nairobi, Kenya. 74 pp.
Sources of illustration
• Dale, I.R. & Greenway, P.J., 1961. Kenya trees and shrubs. Buchanan’s Kenya Estates Limited, Nairobi, Kenya. 654 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.
Author(s)
Nyunaï Nyemb
Institut de Recherches Médicales et d’Etudes des Plantes Médicinales, B.P. 3805, Yaoundé, Cameroon


Editors
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
Photo editor
G.H. Schmelzer
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article:
Nyemb, Nyunaï, 2010. Celtis africana Burm.f. 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, tree habit; 2, flowering twig; 3, fruiting branch.
Redrawn and adapted by Achmad Satiri Nurhaman




obtained from SANBI




obtained from SANBI




obtained from SANBI




obtained from Zimbabweflora



Celtis africana


Celtis africana



obtained from Zimbabweflora