Prota 7(1): Timbers/Bois d’œuvre 1
Fl. Seneg. tent. 1(6): 228 (1832).
Papilionaceae (Leguminosae - Papilionoideae, Fabaceae)
2n = 22
Small-leaved bloodwood, barwood (En). Muvilu (Po).
Origin and geographic distribution
Pterocarpus lucens has a remarkably disjunct distribution area, as a result of which two subspecies are distinguished: subsp. lucens occurring in the savanna zone from Senegal to Ethiopia and Uganda, and subsp. antunesii (Taub.) Rojo, occurring from southern Angola and northern Namibia to Mozambique.
The wood is locally used for joinery, flooring, furniture, cabinet making and implements. It is also suitable for heavy construction, mine props, shipbuilding, vehicle bodies, sporting goods, toys, novelties, railway sleepers, veneer and plywood. Locally in the Sahel region it is one of the preferred timbers for posts and light carpentry in houses, huts, cereal stores and shelters. It was formerly used for wagon wheel rims. The wood is commonly used as firewood, giving a hot flame and little smoke.
Cooked young leaves are eaten as a vegetable; they serve as appetizer. The foliage is an important forage for all kinds of livestock. The bark is locally used for tanning and in medicinal preparations to treat diarrhoea and tapeworm infections. A root decoction is applied against lumbago and to treat kidney complaints. Leaf macerations are used to treat headache.
Logs are short and usually fluted. The heartwood is creamy white and indistinctly demarcated from the sapwood. The grain is straight or interlocked, texture moderately fine. Freshly cut wood has an offensive smell. The wood is moderately heavy to heavy; wood from Mozambique has a density of 820–920 kg/m³ at 12% moisture content, wood from Zambia 700–800 kg/m³. The wood usually dries well with little deformation. Shrinkage rates are usually low, from green to oven dry less than 3% radial and 5% tangential, but they can also be fairly high, from green to oven dry up to 5.7% radial and 9.8% tangential. Once dry, the wood is stable in service. At 12% moisture content the modulus of rupture of wood from Zambia is 102 N/mm², modulus of elasticity 10,200 N/mm², compression parallel to grain 51 N/mm² and Janka side hardness 9,090 N. Although the wood is hard and tough, it generally saws and works well, although interlocked grain may cause some picking up in planing. It splits easily, but holds nails and screws well. It turns well. When a filler is used, the results of painting, polishing and varnishing are satisfactory. The wood is moderately durable, but resistant to impregnation with preservatives. The sawdust may cause irritation in workers. The wood contains a yellowish dye.
The feed value of the leaves is fairly high: 0.77 and 0.65 forage unit/kg dry matter for green and dry leaves, respectively. The crude protein content (dry matter basis) decreases from 19.4% in green leaves to 14.9% in dry leaves, and digestible nitrogen from 14.9% to 10.4%.
Deciduous shrub or small tree up to 12(–18) m tall; bole straight and cylindrical or low-branched, up to 70(–80) cm in diameter; bark surface pale grey to dark brown, smooth to fissured or scaly, inner bark brown, mottled with yellow and purplish red, exuding a reddish gum on slashing; crown narrow, dense; twigs short-hairy when young. Leaves alternate, imparipinnately compound with (1–)5–7(–9) leaflets; stipules linear, up to 5 mm long, hairy, falling off early; petiole (0.5–)2–3(–4) cm long, rachis (1.5–)3–8(–11) cm long, sparsely hairy, glabrescent; petiolules 2–6 mm long; leaflets alternate to opposite, almost orbicular to ovate or elliptical, (2–)3–8(–9.5) cm × (1–)1.5–5(–6) cm, base rounded to obtuse, apex obtuse to slightly notched, papery, brownish hairy below when young but later glabrescent, with 6–20 pairs of lateral veins. Inflorescence an axillary raceme (2–)6–12(–16) cm long, slightly hairy. Flowers bisexual, papilionaceous; pedicel (5–)8–15(–18) mm long; calyx campanulate, 7–8.5 mm long, almost glabrous, with 5 triangular teeth 2–2.5 mm long; corolla with clawed petals, pale yellow, standard almost circular, up to 15 mm × 13 mm, wings up to 15 mm long, keel up to 12 mm long; stamens 10, fused into a sheath up to 10 mm long, the upper stamen more or less free; ovary superior, stiped, hairy, style up to 6.5 mm long, glabrous towards the top. Fruit an obovate-elliptical, flattened, indehiscent pod 3–5.5 cm long, on a stipe up to 1 cm long and with a papery, wavy wing, glabrous, straw-coloured to greyish or yellowish brown, 1(–2)-seeded. Seed kidney-shaped to oblong, flat to slightly thickened, c. 7 mm × 3 mm, smooth, brown.
Pterocarpus lucens trees often retain their foliage until the second half of the dry season. They flower at the end of the dry season, just before new leaves develop, or flowers appear together with young leaves. Bees commonly visit the flowers and probably act as pollinators. Fruits take about 3 months to mature. The roots have nodules containing nitrogen-fixing bacteria, but Pterocarpus lucens is considered to have comparatively low nitrogen fixation potential. In Senegal the contribution of nitrogen fixation was estimated at 28.9 kg N/ha and 10.8 kg N/ha in ferruginous and sandy soils, respectively.
Pterocarpus is a pantropical genus belonging to the tribe Dalbergieae; it comprises approximately 30 species of which about 15 occur in Africa, 10 in America and 5 in Asia. Two subspecies of Pterocarpus lucens are distinguished: subsp. lucens (synonym: Pterocarpus abyssinicus Hochst. ex A.Rich.) and subsp. antunesii (synonym: Pterocarpus antunesii (Taub.) Harms), the latter usually having smaller leaflets and a more hairy calyx.
Pterocarpus lucens occurs in open and wooded savanna up to 1200(–1500) m altitude, preferring deep sandy soils, but also on clay soils including alluvial plains, where it usually becomes a tree, and on rocky outcrops including limestone, where it often remains a shrub. It is usually found in drier habitats than Pterocarpus erinaceus Poir., in regions with a mean annual rainfall of 300–700 mm. Locally it is common; it often grows gregariously and may form nearly pure stands. In southern Africa it is nowhere common and typical of dry deciduous forest.
Seeds can be stored for up to 4 years. The weight of 1000 seeds is about 200 g. Optimum temperatures for germination are in the range of 25–35°C and seedlings are light demanding. Trees can be managed by lopping to extend the period that they bear leaves. In Niono (Mali; average annual rainfall 500 mm) the foliage yield is 3.5 t dry matter per ha for a nearly pure stand of 1600 stems/ha.
Genetic resources and breeding
Locally the pressure on populations of Pterocarpus lucens is high because of the popularity of its wood for house construction, increasing fuelwood demand and frequent use for forage. In Burkina Faso it has been noted that in dry years many Pterocarpus lucens trees may die; they have a comparatively poorly developed root system that is probably often damaged by termites, and are probably often weakened by regular harvesting of foliage for fodder.
Like some other Pterocarpus species, Pterocarpus lucens is important as a source of forage during a large part of the dry season. It is of high value for local people, also because of its other uses as timber, vegetable, medicinal plant and fuelwood tree. Research on sustainable management practices is needed to stop its decline and ensure its survival in the longer term.
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Correct citation of this article:
Lemmens, R.H.M.J., 2008. Pterocarpus lucens Lepr. ex Guill. & Perr. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
obtained from P. Ekpe NSBP
obtained from P. Ekpe NSBP
obtained from P. Ekpe NSBP
obtained from P. Ekpe NSBP
obtained from P. Ekpe NSBP