Prota 7(2): Timbers/Bois d’œuvre 2
Mildbr., Wiss. Erg. Deut. Zentr.-Afr. Exped., Bot. 3: 241, pl. 27 (1911).
Caesalpiniaceae (Leguminosae - Caesalpinioideae)
Origin and geographic distribution
Mildbraediodendron excelsum is widespread from Ghana east to DR Congo, southern Sudan and western Uganda.
The wood, known as ‘muyati’ in Uganda, is used for heavy construction, flooring and railway sleepers, and also as firewood and for charcoal production. Mildbraediodendron excelsum is occasionally planted as a shade tree in coffee, cocoa and banana plantations, and as an ornamental tree.
The heartwood is whitish yellow to pinkish, turning pale brown to ochrous brown upon exposure, with attractive paler markings; it is clearly demarcated from the sapwood. The texture is moderately coarse. The wood is heavy. It is difficult to nail and has a tendency of splitting. It is durable.
Mildbraedin, a kaempferol tetraglycoside, has been isolated from an aqueous methanol extract of leaves.
Deciduous, medium-sized to large tree up to 50 m tall; bole branchless for up to 20 m, straight or slightly sinuous, cylindrical, up to 90 cm in diameter, with triangular buttresses up to 3 m high; bark surface scaly with rectangular scales or slightly longitudinally fissured, grey-brown, inner bark thick, fibrous, whitish to pinkish or pale orange, slightly streaked, with whitish exudate; crown large, with spreading branches; twigs sparsely short-hairy to glabrous. Leaves alternate, imparipinnately compound with 12–19 pairs of leaflets; stipules small, caducous; petiole and rachis together 25–45 cm long, grooved; petiolules 3–4 mm long, hairy; leaflets alternate to opposite, ovate-oblong to lanceolate-oblong, 2–8 cm × 1–2.5 cm, rounded at base, obtuse at apex, sparsely short-hairy, with numerous translucent dots, pinnately veined. Inflorescence a lateral raceme on young branches below the leaves, 1–7 cm long, short-hairy. Flowers bisexual or unisexual, yellowish green, with linear, caducous bracteoles at base; pedicel 0.5–1 cm long; calyx globular, 5–7 mm in diameter, splitting into (2–)3 lobes upon opening of the flower; petals absent; stamens 12–18, slightly fused at base; disk flattened, c. 3.5 mm in diameter; ovary superior, with long stipe, 1-celled, style awl-shaped. Fruit a globose pod 4–10 cm in diameter, greenish, indehiscent, with 1–3(–5) seeds embedded in soft, yellowish pulp. Seeds ellipsoid, 4–7 cm long, brown.
Mildbraediodendron excelsum trees grow slowly. The fruits are commonly eaten by elephants, which disperse the seeds. Leaves and fruits are eaten by chimpanzees.
Mildbraediodendron comprises a single species. In recent classifications it is usually placed in the tribes Swartzieae or Sophoreae of the family Papilionaceae (Leguminosae - Papilionoideae), and it is related to Aldina from tropical America and Cordyla from mainland Africa and Madagascar. Its flowers, lacking petals and with more than 10 stamens, do not have the characteristic papilionaceous structure, and therefore Mildbraediodendron was until recently usually classified within Caesalpiniaceae.
Mildbraediodendron excelsum occurs in lowland rainforest up to 1000 m altitude. In Cameroon it occurs mainly in semi-deciduous forest.
To obtain seed for propagation, ripe fruits should be collected and seeds extracted and gradually dried. The seeds can be stored for some time in a cool and dry place, but they are susceptible to insect attack; it is recommended to mix the seeds with ash. Wildlings are sometimes also collected for planting. In Uganda Mildbraediodendron excelsum has been planted in mixed plantations with Entandrophragma spp. and Maesopsis eminii Engl. The tree can be managed by lopping and pollarding.
Genetic resources and breeding
Although Mildbraediodendron excelsum is quite widespread, it is in part of its distribution area rare, especially in West Africa.
It has been suggested more than once that Mildbraediodendron excelsum is a timber tree of potential commercial importance. This is certainly the case where it occurs abundantly, but for sustainable exploitation the low growth rate should be taken into consideration.
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Correct citation of this article:
Lemmens, R.H.M.J., 2010. Mildbraediodendron excelsum Harms. 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.
wood in transverse section
wood in tangential section