Prota 7(2): Timbers/Bois d’œuvre 2
Man. ess. forest. Congo: 85 (1923).
Caesalpiniaceae (Leguminosae - Caesalpinioideae)
Origin and geographic distribution
Gilletiodendron mildbraedii occurs from southern Cameroon to the Central African Republic and DR Congo.
The wood is suitable for heavy construction, heavy flooring, joinery, interior trim, ship building, vehicle bodies, mine props, railway sleepers, handles, ladders, sporting goods, toys, novelties, agricultural implements, carving, turnery, veneer and plywood. The bark is used in traditional medicine in DR Congo to treat syphilis.
The heartwood is reddish brown to chocolate brown, mottled and with a satiny shine; it is distinctly demarcated from the yellowish white, up to 8 cm wide sapwood. The grain is usually straight, occasionally slightly interlocked, texture fine. Quarter-sawn surfaces show some streaks.
The wood is heavy, with a density of 950–1060 kg/m³ at 12% moisture content, and very hard. It air dries slowly, and shows a tendency of surface checking and sometimes also end splitting. The rates of shrinkage upon drying are high. Quarter-sawing is recommended before drying. Once dry, the wood is moderately stable in service. At 12% moisture content, the modulus of rupture is 204–270 N/mm², compression parallel to grain 69–82 N/mm², cleavage 24 N/mm and Chalais-Meudon side hardness 7.3. The wood saws rather easily but slowly due to its hardness; it has a serious blunting effect on saw teeth and working tools. It can be planed to a nice surface, and polishes well. Pre-boring is recommended for nailing. The bending properties are good. The wood is fairly durable, but is susceptible to the fungus Coniophora cerebella and to marine borer attacks. It is resistant to impregnation by preservatives.
Medium-sized to large tree up to 45 m tall; bole usually straight and cylindrical, up to 110 cm in diameter, with large buttresses up to 6.5 m high; bark surface rough, dark grey, inner bark reddish or pinkish brown; twigs short-hairy. Leaves alternate, imparipinnately compound with 14–28 leaflets; stipules linear, early caducous; petiole and rachis together 5–15 cm long, grooved; leaflets usually alternate, sessile, oblong to nearly rectangular, asymmetrical, 1–4(–5) cm × 0.5–1.5(–2) cm, with some translucent dots. Inflorescence an axillary or terminal panicle 3–13 cm long, densely hairy, many-flowered. Flowers bisexual, nearly regular, whitish; pedicel 3–5 mm long; sepals 4, free, ovate to oblong, 1–3 mm long, 1 slightly larger than the other 3, reflexed; petals 5, free, linear-oblong, 3–4 mm long; stamens 10, free, unequal in length, 4–6 mm long; ovary superior, elliptical-oblong, c. 1.5 mm long, with short stipe, glabrous, 1-celled, style slender, 2.5–3.5 mm long. Fruit an obliquely obovate to elliptical, flattened pod, 3.5–6 cm × 2–3 cm, pointed at apex, smooth to finely warty, dehiscing with 2 woody valves, few-seeded. Seeds flattened. Seedling with epigeal germination; hypocotyl 5–7 cm long, epicotyl 2–3 cm long; first 2 leaves opposite, with c. 8 leaflets.
Gilletiodendron comprises about 5 species and occurs in West and Central Africa. It is classified in the tribe Detarieae, in which its position is still unresolved.
Gilletiodendron glandulosum (Portères) J.Léonard is a small to medium-sized tree up to 20 m tall endemic to Mali, where it occurs in small pockets of savanna woodland. Its very hard and durable wood is used in house building, especially for support posts and cross beams, and for granaries and beds. Gilletiodendron glandulosum has been recommended for reafforestation. The seeds are reportedly edible. Gilletiodendron glandulosum is included in the IUCN Red List as vulnerable.
Gilletiodendron kisantuense (Vermoesen ex De Wild.) J.Léonard is a small to medium-sized tree up to 30 m tall known from Côte d’Ivoire, Gabon, Congo, DR Congo and northern Angola. The wood is probably used in house building.
Gilletiodendron pierreanum (Harms) J.Léonard is a medium-sized to large tree up to 45 m tall, with bole branchless for up to 20 m, usually fluted and with buttresses, occurring in southern Cameroon, Equatorial Guinea and Gabon. Its wood is used for joinery, furniture and implements.
Gilletiodendron mildbraedii occurs in lowland rainforest, often near rivers.
A 30 m tall tree with a bole of 18 m long and 50 cm in diameter yielded 2.2 m³ of timber.
Genetic resources and breeding
Gilletiodendron mildbraedii is fairly widespread and there are no signs that it is threatened by genetic erosion.
The hard wood, large buttresses and fluted bole are major drawbacks for larger-scale commercial exploitation of Gilletiodendron spp. As suppliers of durable wood for local house construction, they will remain of local importance.
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Correct citation of this article:
Lemmens, R.H.M.J., 2010. Gilletiodendron mildbraedii (Harms) Vermoesen. 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.