Prota 7(2): Timbers/Bois d’œuvre 2
Trans. Linn. Soc. 25: 314 (1865).
Caesalpiniaceae (Leguminosae - Caesalpinioideae)
Origin and geographic distribution
Crudia senegalensis is widespread in West Africa, from Guinea-Bissau east to south-western Nigeria.
The very heavy and hard wood is rarely used, but it has been used for boards in Sierra Leone. The tree is valued as an ornamental shade tree.
The wood is greyish brown, often dark brown in the centre of the log. It has a moderately fine texture and it is very hard, making it very difficult to saw and work.
Small to medium-sized tree up to 30 m tall; bole often low-branching and crooked, up to 90(–100) cm in diameter, with narrow buttresses; bark surface irregularly scaly, greyish brown, inner bark fibrous, reddish brown; crown spreading; twigs glabrous. Leaves alternate, imparipinnately compound with 6–12 leaflets; stipules narrowly ovate, united at base, 1–3(–4) cm long, persistent; petiole 1–2(–2.5) cm long, rachis up to 15(–19) cm long; petiolules 1–3 mm long, twisted; leaflets alternate, ovate-elliptical to obovate, (1.5–)5–10(–15) cm × (1–)2–5(–7) cm, slightly asymmetrical, glabrous. Inflorescence an axillary or terminal raceme up to 21 cm long, glabrous, loosely flowered. Flowers bisexual, regular, greenish; pedicel 1.5–2.5 cm long; sepals usually 4, elliptical, 5–7 mm long, glabrous outside, short-hairy inside; petals absent; stamens 10, free, 1–1.5 cm long; ovary superior, c. 0.5 cm long, hairy, style c. 1 cm long. Fruit an elliptical to nearly round, flattened pod 5–12 cm × 4–7 cm, hairy, dehiscing by 2 woody valves, 1–2-seeded. Seeds elliptical to nearly round, flattened, 4–6 cm long, glabrous, brown. Seedling with epigeal germination, but seemingly hypogeal; hypocotyl c. 0.5 cm long, epicotyl 14–20 cm long; cotyledons remaining within the seed coat; first leaves alternate, with 3(–4) pairs of opposite leaflets.
There is no information on growth rates of Crudia senegalensis, but probably trees grow slowly. In Gabon young trees of Crudia gabonensis Pierre ex De Wild. reached a mean annual bole diameter growth of 8 mm, older trees 1–3 mm. In Côte d’Ivoire trees of Crudia senegalensis flower in October to February and fruits mature in January to March(–May).
Crudia comprises about 55 species, of which about 30 in tropical Asia, 10 in tropical America and 10 in West and Central Africa. Its affinity is still uncertain. Several other Crudia spp. become medium-sized and sometimes even large trees, and their wood may be used occasionally, although it is extremely hard and difficult to cut. One of these is Crudia gabonensis, which may become 50 m tall with a bole up to 125 cm in diameter; it is found from Côte d’Ivoire to Gabon and Congo.
Crudia senegalensis occurs in lowland rainforest, often in swamp forest and along rivers and lagoons, up to 50 m altitude.
There are about 100 seeds per kg. Germination starts 2–3 months after sowing and the germination rate is low. Pre-treatment of the seeds is needed to obtain fair germination results.
Genetic resources and breeding
Although Crudia senegalensis is widespread in West Africa, it occurs usually scattered, most commonly in riverine and swamp forest. Therefore, it may be liable to genetic erosion when these forest types decline.
The timber of Crudia senegalensis and other Crudia spp. will not become commercially interesting because of scattered occurrence and low growth rates of the trees, and the difficulties in sawing and working the wood.
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Correct citation of this article:
Lemmens, R.H.M.J., 2010. Crudia senegalensis Planch. ex Benth. 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.