Prota 7(2): Timbers/Bois d’œuvre 2
Journ. Linn. Soc., Bot. 22: 521 (1887).
Celtidaceae (APG: Cannabaceae)
Celtis durandii Engl. (1900).
Bastard white stinkwood, forest celtis (En).
Origin and geographic distribution
Celtis gomphophylla is widespread, from Côte d’Ivoire east to Ethiopia and Kenya, and south to Angola, Zimbabwe, Mozambique and eastern South Africa. It is also found in Mayotte and Madagascar.
The wood, sometimes traded as ‘ohia’, is commonly used for light construction, light flooring, joinery, furniture, cabinet work, canoes, ladders, sporting goods, agricultural implements, tool handles and matches. It is suitable for ship building, vehicle bodies, hardboard and particle board. It is also used as firewood and for charcoal production.
In traditional medicine, a leaf decoction is used for the treatment of cardiovascular disorders in Cameroon. In southern Nigeria a root decoction is used to treat fever and menstrual pains. Celtis gomphophylla is planted as a shade tree for crops and to improve soil conditions.
The heartwood is whitish, turning slightly darker upon exposure, and not distinctly demarcated from the sapwood. The grain is usually interlocked, texture moderately fine. The wood has a persistent unpleasant smell.
The wood is medium-weight, with a density of 510–600 kg/m³ at 12% moisture content. It is softer and less strong than that of the other Celtis spp. It usually air dries rapidly without serious degrade, but is liable to blue stain attack; dipping in anti-stain solution before stacking is recommended. It kiln dries fairly well, but some cupping and collapse around knots may occur. The rates of shrinkage from green to oven dry are 2.1–4.0% radial and 3.6–6.5% tangential.
The wood saws and works well with both machine and hand tools, but cutting edges should be kept sharp. A reduced cutting angle of 15° is recommended when machining quarter-sawn stock to prevent tearing along the grain. The wood holds nails and screws moderately well, but has a tendency to split; pre-boring is therefore advised. Boring and mortising should be done with strong support. The gluing properties are good, steam bending properties moderate. The wood does not turn well. Generally, it has a low durability, being susceptible to attack by fungi and Lyctus, but it is reported to be moderately durable in DR Congo and southern Africa. The wood can readily be treated with preservatives when using pressure methods. Wood dust may cause irritation to nose and throat.
Leaf extracts showed a vaso-relaxant effect on thoracic aorta of rats.
Evergreen or deciduous shrub or small to medium-sized tree up to 30(–60) m tall; bole branchless for up to 13 m, often irregular and gnarled, up to 40(–120) cm in diameter, often fluted, sometimes with low but spreading buttresses; bark surface smooth, whitish grey to greenish grey, inner bark granular, with yellow and brown bands; crown with spreading branches; twigs sparsely whitish hairy. Leaves alternate, simple; stipules linear, 2–6 mm long, whitish hairy, caducous; petiole 0.5–1 cm long, slightly grooved above; blade ovate-elliptical to oblong-elliptical or lanceolate, 5–16 cm × 2–5(–8) cm, cuneate to rounded and asymmetrical at base, usually with long-acuminate apex, margins entire or sometimes toothed in upper part, papery, glabrous, often rough above, prominently 3-veined from the base and additionally with 3–5 pairs of lateral veins. Inflorescence an axillary cyme up to 1.5 cm long, short-hairy. Flowers unisexual or bisexual, regular, 4–5-merous, small; tepals 1–2 mm long, hairy; stamens free, c. 1.5 mm long; ovary superior, ovoid, slightly hairy or glabrous, 1-celled, styles 2, unbranched; male flowers few to many together, with pedicel 3–7 mm long and rudimentary ovary; female flowers and/or bisexual flowers 1–few together, with pedicel often longer, female flowers with rudimentary stamens. Fruit a conical-ovoid drupe 4–7 mm long, dark yellow when ripe, glabrous; stone angular-ovoid, c. 4 mm long, pitted, dark brown, 1-seeded.
Celtis gomphophylla grows rapidly in full sunlight, but growth is poor or stops completely under shaded conditions. In Côte d’Ivoire trees flower in March. The flowers are pollinated by insects such as bees. Fruits mature about 2 months after flowering. Trees produce fruits in abundance and these are relished by monkeys, chimpanzees and probably also birds, which may serve as seed dispersers.
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.
Celtis gomphophylla has a wide ecological amplitude. In Central Africa it mostly occurs in the understorey of moist evergreen and semi-deciduous rainforest and riverine forest, often in secondary forest. In West Africa it seems to be nearly restricted to upland forest. In Uganda it is an early successor of forest gaps and is also found in forest edges, thickets, woodland and wooded grassland. In western Kenya it is locally dominant in rainforest in areas with a mean annual rainfall of 1400–1900 mm. In South Africa it is restricted to coastal regions, whereas in Madagascar it is often found along watercourses on alluvial soils. Celtis gomphophylla can be found up to 1750(–2000) m altitude.
Celtis gomphophylla is propagated by seed and wildlings. Fruit stones are obtained from fallen mature fruits. After cleaning and drying they can be stored for up to 2 months in sealed containers, or they are sown directly in the nursery or in the field. Pre-sowing treatment is not necessary as seeds germinate readily.
Genetic resources and breeding
In view of its wide distribution and acceptance of variable habitat conditions, Celtis gomphophylla is not likely to be threatened by genetic erosion. It is locally common and is currently not overexploited. However, it is rare in West Africa and is a protected species in South Africa.
It is unlikely that Celtis gomphophylla will become commercially more important as a timber tree because of its often poorly shaped and small-sized bole and because of the persistent unpleasant smell of the wood. The vaso-relaxant properties of the leaf support its use in traditional medicine for cardiovascular disorders; this warrants further research for potential drug development. Celtis gomphophylla seems to be useful for forest restoration and possibly also for planting in agroforestry systems.
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Correct citation of this article:
Obeng, E.A., 2010. Celtis gomphophylla Baker. 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.