Prota 7(1): Timbers/Bois d’œuvre 1
Bull. Soc. Bot. France 58, mém. 8: 155 (1912).
Mimosaceae (Leguminosae - Mimosoideae)
Origin and geographic distribution
Calpocalyx brevibracteatus occurs from Sierra Leone to Cameroon.
The wood is locally used in house building, e.g. for posts and planks, for tool handles and canoes, and as firewood. The bark is used in traditional medicine; a maceration is applied as a mouthwash to treat sores, and the inner bark is used against stomach-ache. Ash of burnt pods is used in soap-making or as salt. The seeds are edible after cooking.
The heartwood is dark brown, often variegated with red and black, and distinctly demarcated from the greyish sapwood. The grain is irregular, texture moderately coarse. The wood is heavy, with a density of about 830 kg/m³ at 15% moisture content, and hard. At 12% moisture content, the modulus of rupture is about 135 N/mm², modulus of elasticity 16,650 N/mm², compression parallel to grain 59 N/mm² and Janka side hardness 11,365 N. The wood is difficult to work, but attractive when properly finished. It is durable. The firewood quality is inferior; the wood crackles when burnt.
The leaves and bark contain tannins.
Medium-sized to fairly large tree up to 30(–40) m tall, but usually smaller; bole straight, cylindrical, up to 50(–80) cm in diameter, without buttresses or with short buttresses; bark grey to dark brown; crown dense, rounded. Leaves alternate, bipinnately compound with a single pair of pinnae; stipules linear, caducous; petiole short, with large gland at apex on upper side; axes of pinnae 15–20 cm long; leaflets in 5–6 pairs per pinna, opposite, elliptical, 7–15 cm × 2–6 cm, acuminate, leathery, glabrous. Inflorescence an axillary or terminal pendent spike 6–10 cm long, arranged in panicles, many-flowered; bracts very small. Flowers bisexual, regular, 5-merous, small, sessile, hairy; calyx campanulate, c. 2 mm long, shortly toothed; petals fused at base, c. 4 mm long, pinkish to brownish orange; stamens 10, fused at base, much longer than petals, with glands at apex; ovary superior, slightly stalked, hairy, 1-celled, style long and slender. Fruit an obliquely oblong pod up to 17 cm × 4.5 cm, strongly flattened, long-attenuate at base, rounded at apex, woody, 2-valved, 5–10-seeded. Seeds angular, flattened. Seedling with epigeal germination; hypocotyl 4–5 cm long, finely reddish-hairy, epicotyl 3–4 cm long; cotyledons thick, fleshy, oblong, notched, purplish.
Calpocalyx comprises 11 species and is restricted to the more humid forest types of West and western Central Africa. It is related to Xylia , which differs in its head-like inflorescences. In western Central Africa 9 species occur, in West Africa 2.
Calpocalyx aubrevillei Pellegr. occurs from Sierra Leone to Côte d’Ivoire, and is locally common in evergreen forest on moist soils and along watercourses, especially in Liberia. Its wood is used for construction, planks and canoes, but it is much lighter in weight, not durable and liable to warping. Ash from the wood is used for vegetable salt, the seeds are edible after cooking, and a relieving salve is made from pounded seeds in palm oil to treat women’s aching breasts. Calpocalyx aubrevillei is a fairly large tree up to 32 m tall, which differs from Calpocalyx brevibracteatus in its usually larger leaflets, which are more conspicuously veined and shortly hairy, and in its larger bracts, cylindrical calyx and larger pods.
The branches of Calpocalyx brevibracteatus are hollow and may be inhabited by ants. The fruits dehisce explosively during the dry season, shattering the seeds. In Sierra Leone flowering is in September–December, and fruiting in January–April.
Calpocalyx brevibracteatus usually occurs in evergreen forest, sometimes in semi-deciduous forest and gallery forest. The occurrence reaches a maximum in areas with about 2500 mm/year of rainfall. Calpocalyx brevibracteatus is a fairly common understorey tree, especially in Liberia and Ghana. It can be found on sandy-loamy, sandy-clayey and lateritic soils.
Natural regeneration occurs often gregariously in the shade, but in evergreen forest in relatively exposed localities. One kg contains approximately 3000 seeds. The seed has a high germination rate, and germination starts after 6–15 days. Freshly felled logs sink in water and cannot be transported by floating down a river.
Genetic resources and breeding
Calpocalyx brevibracteatus is widespread and locally common, and not under threat of genetic erosion.
Calpocalyx brevibracteatus trees are often of too small size to be of commercial importance as a timber, the boles often being short and not reaching the minimum diameter limit allowed for logging. They will remain of some importance for local house building because of the durability of the wood.
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Correct citation of this article:
Lemmens, R.H.M.J., 2006. Calpocalyx brevibracteatus Harms. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.