Prota 7(2): Timbers/Bois d’œuvre 2
Engl. & Drude, Veg. Erde 9, III, 2: 282 (1921).
Origin and geographic distribution
Eriocoelum microspermum occurs from Cameroon and the Central African Republic south to DR Congo and Angola.
In DR Congo stems are used for poles. The wood is suitable for construction, flooring, joinery, interior trim, ship building, vehicle bodies, furniture, sporting goods, handles, ladders, agricultural implements, boxes, crates, turnery, veneer, plywood, hardboard and particle board. Eriocoelum microspermum provides firewood of excellent quality. The bark is used as traditional medicine to treat cough, enteritis and venereal diseases.
Production and international trade
The timber is known under the trade name ‘kadiamikani’, but trade volumes are probably only small.
The heartwood is pinkish brown to reddish brown, and distinctly demarcated from the pale grey to brownish yellow, up to 7 cm wide sapwood. The grain is usually straight, but with occasional irregular patches, texture medium to fine and even. Radial surfaces show a mottled and ribbon figure, and the wood is lustrous.
The wood is medium-weight, with a density of 560–670 kg/m³ at 12% moisture content, and very tough and resilient. The shrinkage rates in drying are quite high. At 12% moisture content, the modulus of rupture is 97–139 N/mm², modulus of elasticity 12,000 N/mm² and compression parallel to grain 53–66 N/mm².
The wood is easy to saw. It planes well and usually shows no picking-up of grain. It takes a good finish. The wood has good nailing properties; it does not split and holds nails well. Larger logs are suitable for veneer production by peeling. The wood is moderately durable. It is rarely attacked by termites, the sapwood is not susceptible to Lyctus attack, but the wood is liable to marine borer attack.
Monoecious, small to medium-sized tree up to 30(–35) m tall; bole usually straight, branchless for up to 15 m, up to 80 cm in diameter; young twigs reddish brown short-hairy. Leaves alternate, paripinnately compound with 2–3 pairs of leaflets; stipules absent; petiole very short or absent, rachis 8–14 cm long; petiolules stout, up to 8 mm long; leaflets opposite, elliptical, 12–35 cm × 5–13 cm, lowest pair of leaflets smallest and stipule-like, cuneate to rounded at base, acuminate at apex, margins entire, leathery, nearly glabrous, pinnately veined with c. 15 pairs of lateral veins. Inflorescence a terminal or axillary panicle up to 30 cm long, short-hairy. Flowers unisexual, regular, 5-merous; pedicel often recurved, up to 5 mm long; sepals nearly free, c. 1.5 mm long, short-hairy outside; petals free, 3–5.5 mm long, whitish, inside with 2 densely hairy scales at base; stamens 8, free, up to 5 mm long; disk annular, with wavy margin; ovary superior, nearly globose, hairy, 3-celled, style c. 2.5 mm long; male flowers with rudimentary ovary, female flowers with reduced stamens. Fruit a globose capsule 1–2 cm × 1.5–2.5 cm, slightly 3-lobed, orange when fresh, dehiscent with 3 woody valves, inside at base long-hairy, 3-seeded. Seeds ellipsoid, c. 1.5 cm long, smooth, brown, with red cup-shaped aril at base. Seedling with hypogeal germination; epicotyl 3–4 cm long, short-hairy; first leaves alternate, simple.
Eriocoelum comprises about 10 species and is confined to mainland tropical Africa. Eriocoelum kerstingii Gilg ex Engl. occurs from Guinea Bissau and Mali east to Sudan and Uganda, and south to Gabon and DR Congo. It is a small tree up to 15 m tall with a bole diameter up to 50 cm. Its pale brown wood is strong and used for construction, furniture, axe-handles and pestles.
Eriocoelum macrocarpum Radlk. ex Engl. is a medium-sized tree up to 30(–35) m tall with bole branchless for up to 20 m and up to 60 cm in diameter. It occurs in Nigeria, Cameroon, Equatorial Guinea, Gabon, Congo and western DR Congo. Its pale brown to pinkish brown wood has properties and uses similar to that of Eriocoelum microspermum.
Eriocoelum pungens Radlk. is a shrub or small tree distributed from Liberia to Nigeria. The wood is used in house building and for rafters.
Eriocoelum microspermum is found in humid forest, often in swampy or periodically inundated forest, up to1400 m altitude.
Logs have to be processed quickly after felling to avoid serious checking. In DR Congo a bole of 5.6 m long and 43 cm in diameter yielded 0.5 m³ of wood.
Genetic resources and breeding
Eriocoelum microspermum is fairly widespread and there are no indications that it is under severe pressure.
As a timber producer Eriocoelum microspermum is not likely to become more important because the bole dimension is often rather small and the trees usually occur scattered. However, very little is known about this species and other Eriocoelum spp.
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Correct citation of this article:
Bosch, C.H., 2011. Eriocoelum microspermum Radlk. ex Engl. 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.