Prota 7(1): Timbers/Bois d’œuvre 1
Notul. Syst. (Paris) 2: 293 (1912).
Papilionaceae (Leguminosae - Papilionoideae, Fabaceae)
Amphimas klaineanus Pierre ex Pellegr. (1912).
Origin and geographic distribution
Amphimas ferrugineus occurs in south-western Cameroon, Equatorial Guinea, Gabon, Congo, western DR Congo and northern Angola.
The wood (trade names: lati, bokanga) is used for interior construction, carpentry, flooring, planks, interior trim, joinery, furniture, frames, crates, boxes, toys, novelties, veneer and plywood. A bark decoction is used in traditional medicine to treat dysmenorrhoea, blennorrhoea and as poison antidote: bark pulp is applied to mumps.
Production and international trade
Amphimas ferrugineus and Amphimas pterocarpoides Harms are both traded as lati. In 2003 Cameroon exported about 70 m³ of lati logs and 130 m³ of sawnwood. In 2004 Cameroon exported about 2500 m³ of lati logs and 110 m³ of sawnwood.
The heartwood is yellowish brown, often with whitish markings that darken with age, and more or less distinctly demarcated from the 5–8 cm thick, yellow-white to pale brown sapwood. The grain is usually straight, sometimes wavy, texture moderately coarse. The wood has a coarse silver figure.
The wood is moderately heavy. At 12% moisture content, the density is 690–750 kg/m³. The rates of shrinkage during drying are moderately high, from green to oven dry 3.4% radial and 8.5% tangential. The wood dries slowly, with severe risk of deformation. It is recommended to quarter-saw the timber before drying. Some pre-drying is recommended before kiln drying. After drying, the wood is moderately stable in service.
At 12% moisture content, the modulus of rupture is 133–182 N/mm², modulus of elasticity 11,300–13,600 N/mm², compression parallel to grain 55–67 N/mm², cleavage 21–30 N/mm, and Chalais-Meudon side hardness 3.9–7.2.
The wood saws and works well with standard equipment, and can be planed to a smooth surface, but with some dulling effect on cutting edges. The nailing and screwing properties are good, with satisfactory holding properties, but pre-boring is often needed. The gluing, staining and painting properties are satisfactory. The wood is suitable for sliced veneer and plywood production. It is moderately durable to non-durable; it is susceptible to dry-wood borer and marine borer attack, but often moderately resistant to fungal and termite attacks. The heartwood is moderately resistant to impregnation by preservatives, the sapwood is permeable.
Large deciduous tree up to 45(–50) m tall; bole straight, cylindrical, branchless for up to 25(–30) m, up to 120(–150) cm in diameter, with thick buttresses; bark surface smooth to slightly rough, finely fissured or with rectangular scales, grey to greyish brown, inner bark thick, soft, fibrous, creamy to yellowish, exuding a red exudate; crown hemispherical; young twigs densely reddish brown hairy. Leaves arranged spirally in tufts at the ends of branches, imparipinnately compound with 11–19 leaflets; stipules leafy, up to 2.5 cm long, caducous; petiole 2.5–4.5 cm long, rachis up to 30 cm long but sometimes longer, densely hairy; leaflets alternate to opposite, with thread-like stipels at base of 2–3 mm long petiolules, (3–)6–18 cm × (1.5–)2–6 cm, ovate to oblong or elliptical, rounded to shortly acuminate at apex, densely short-hairy below, pinnately veined with veins distinct below. Inflorescence a lax terminal or axillary compound raceme c. 20 cm long, strongly branched, many-flowered. Flowers bisexual or male, regular, 5-merous, fragrant; pedicel c. 1 mm long; calyx campanulate, c. 3 mm long, with short lobes, densely brown hairy; petals free, equal, c. 5 mm long, deeply 2-lobed, whitish; stamens 10, fused at base, c. 4 mm long; ovary superior, stipitate, densely to sparsely hairy, style slender, c. 3.5 mm long. Fruit a pendulous, flat, elliptical to oblong pod, 15–22 cm × 5–7 cm, with large papery wing all around, reticulately veined, golden brown, indehiscent or slowly dehiscing with 2 valves, 1(–2)-seeded. Seed kidney-shaped, 2–2.5(–3) cm long, brown.
The winged fruits of Amphimas ferrugineus are spread by wind.
Amphimas comprises 2 or 3 species, and is confined to West and Central Africa. The affinity of the genus is still uncertain. It is usually classified within the Sophoreae tribe of Papilionaceae, but has also been classified in Caesalpiniaceae because of its corolla which lacks the typical papilionaceous structure. Amphimas pterocarpoides differs from Amphimas ferrugineus in its almost glabrous leaflets having inconspicuous veins.
Amphimas ferrugineus occurs in dense evergreen forest up to 500 m altitude.
In Cameroon the minimum diameter for felling is 50 cm. After felling, logs should be removed rapidly from the forest because they are liable to blue stain attack. When left for longer periods, they should be treated with preservatives. Usually, logs float in water and thus can be transported by river.
Amphimas ferrugineus may be threatened by genetic erosion because it has a rather limited area of distribution and specific ecological requirements. It does not seem to occur in high densities, and is uncommon or absent in several regions, e.g. in the sedimentary basin of western Gabon.
Amphimas ferrugineus occurs in an area where many timber species with better wood are still available, and therefore it has poor prospects as a timber tree of commercial importance in the near future. However, it is poorly known, and research may reveal unexpected possibilities.
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Correct citation of this article:
Lemmens, R.H.M.J., 2008. Amphimas ferrugineus Pierre ex Pellegr. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.