Prota 7(1): Timbers/Bois d’œuvre 1
Acta Bot. Neerl. 14: 455 (1966).
2n = 50
Trichilia heudelotii Planch. ex Oliv. (1868).
Origin and geographic distribution
Trichilia monadelpha occurs from Guinea Bissau east to the Central African Republic and DR Congo, and south to northern Angola (Cabinda).
The wood is used in house building, especially for piles. It is locally favoured for wood carving, e.g. for making masks and canoes. It is suitable for light flooring, joinery, interior trim, ship building, vehicle bodies, furniture, cabinet work, boxes, crates, toys, novelties, veneer, plywood, hardboard and particle board, as well as pulpwood for paper production. It is also used as firewood and for charcoal production.
Trichilia monadelpha is an important medicinal plant, and particularly its bark is commonly used in traditional medicine. A bark decoction or the pulped bark is applied externally to wounds, sores, skin affections including yaws, lumbago and oedema. A bark decoction is drunk to sooth cough, as an analgesic and anthelmintic, and to treat gonorrhoea and syphilis, whereas small amounts of pulped bark are eaten or applied as an enema to treat gastro-intestinal complaints. Bark decoctions serve as an aphrodisiac, ecbolic and abortifacient. A leaf decoction is taken to treat heart complaints, and pounded leaves to treat gonorrhoea and lumbago. The roots are an ingredient in preparations to treat dysentery, and are considered aphrodisiac.
The seed oil is occasionally used in cooking. The reddish brown dye present in the bark has been used for dyeing cloth and hides. Trichilia monadelpha is useful for soil protection and soil improvement.
The heartwood is pale pinkish brown to reddish brown and more or less distinctly demarcated from the whitish brown or greyish brown sapwood. The grain is usually straight, texture fine to moderately coarse. The wood contains latex cells and has a cedar-like odour.
The wood is moderately lightweight, with a density of 510–580 kg/m³ at 12% moisture content. The rates of shrinkage during drying are moderate. The wood is moderately stable in service. It is soft. At 12% moisture content, the modulus of rupture is 63–110 N/mm², modulus of elasticity 9200–9800 N/mm², compression parallel to grain 40–45 N/mm², Janka side hardness 2820 N, Janka end hardness 4270 N and Chalais-Meudon hardness 2.7.
The wood is rather difficult to saw and work because of quickly gumming up and blunting of sawteeth and cutting edges. It planes and finishes satisfactorily, producing nice backsawn and quarter-sawn surfaces. The nailing and gluing properties are good. The wood is moderately durable; it is susceptible to blue stain, dry-wood borer and marine borer attacks, whereas the liability to termite attack is recorded as variable. The heartwood is resistant to impregnation with preservatives, but the sapwood is permeable. The sawdust may cause irritation to the respiratory tracts in wood workers.
The presence of alkaloids and tannins has been demonstrated for the bark. Limonoids have been isolated from bark and roots. Bark extracts showed antiplasmodial activity against chloroquine- and pyrimethamine-resistant Plasmodium falciparum strains (IC50 = 3.6 μg/ml). The leaves contain tannins and flavonoids. Leaf extracts showed activity against several bacteria and fungi, including significant activity against the plant-pathogenic fungus Fusarium oxysporum.
Evergreen, small to medium-sized tree up to 20 m tall; bole straight and cylindrical, often low-branching, up to 40(–60) cm in diameter, without buttresses; bark surface smooth, pale grey to greenish brown or dark brown, inner bark pale brown to pink; crown spreading, open; young branches short-hairy. Leaves alternate, imparipinnately compound with 3–6(–7) pairs of leaflets; stipules absent; petiole 4–13 cm long, rachis (4–)8–20(–23) cm long; petiolules 2–7(–11) mm long; leaflets opposite, ovate to obovate, 4–26 cm × 1.5–9 cm, cuneate to obtuse at base, acuminate at apex, hairy below when young but glabrescent, pinnately veined. Inflorescence an axillary panicle up to 12(–21) cm long, short-hairy; bracts ovate or triangular, up to 5 mm long, caducous. Flowers unisexual, male and female flowers very similar in appearance, regular, 5-merous, greenish yellow or greenish white, fragrant; pedicel up to 2 mm long; receptacle cylindrical, 1–2.5 mm long; calyx cup-shaped, 1.5–2.5 mm long, lobes 1–1.5 mm long; petals free, narrowly oblong, 7–10 mm long; stamens 5.5–7.5 mm long, basal half fused into a tube, hairy inside; ovary superior, globose, 2–3 mm in diameter, densely hairy, (2–)3(–4)-celled, style 3–5 mm long, hairy, stigma head-shaped; male flowers with rudimentary ovary, female flowers with non-dehiscing anthers. Fruit an obovoid to globose capsule 1.5–2.5 cm in diameter, (2–)3(–4)-lobed, with short stipe, dehiscent, up to 6-seeded. Seeds 15–17 mm × 8–11 mm, on a long funicle, seed coat partly fleshy and orange-red, remaining part glossy blackish. Seedling with epigeal germination; hypocotyl 1.5–4 cm long, epicotyl 2–3.5 cm long; cotyledons sessile, thick and fleshy, green.
Flowering often coincides with the development of terminal buds and formation of new shoots. In Nigeria Trichilia monadelpha flowers in the dry season. The flowers are pollinated by insects such as bees. In Guinea the fruits ripen in December–January. The seeds are eaten by birds, which may play an important role in their dispersal.
Trichilia comprises about 90 species, most of them in tropical America. In continental Africa 18 species occur, in Madagascar 6.
Trichilia djalonis A.Chev., a shrub or small tree up to 15 m tall occurring from Guinea to Côte d’Ivoire, closely resembles Trichilia monadelpha, but differs in usually fewer, glabrous leaflets and smaller fruits. A reddish dye can be prepared from the bark of Trichilia djalonis, and probably its wood is occasionally used for similar purposes as that of Trichilia monadelpha.
Trichilia ornithothera J.J.de Wilde, which is a small tree up to 15(–20) m tall occurring from Sierra Leone to Ghana, is also close to Trichilia monadelpha and there is much confusion in the literature. Undoubtedly the wood is used for similar purposes, and the bark in traditional medicine. Trichilia ornithothera is characterized by generally larger and more hairy leaves in comparison with Trichilia monadelpha, and by its usually 2-celled ovary. Trichilia ornithothera is classified as vulnerable in the IUCN Red List.
Trichilia tessmannii Harms (synonyms: Trichilia lanata A.Chev., Trichilia mildbraedii Harms) has nearly the same distribution area as Trichilia monadelpha, but is in most regions less common. It is a medium-sized tree up to 30 m tall, with straight, cylindrical bole up to 80 cm in diameter, and is most easily recognized by its twigs having reddish brown, flaking bark. It has been stated that the wood is used in house building and that it is resistant to termites. The bark is used to treat stomach-ache and as a purgative. In DR Congo cooked fruits are eaten. In Nigeria the seeds are used for rattles and tambourines.
In the past Trichilia welwitschii C.DC. has been much confused with Trichilia monadelpha, but it differs in its 2-celled ovary and fruit. It is a small to medium-sized tree up to 30 m tall with a cylindrical bole up to 45(–60) cm in diameter, which occurs from Nigeria to eastern DR Congo and northern Angola. The wood is probably used for similar purposes as that of Trichilia monadelpha. In DR Congo a bark decoction is administered as an enema to treat haemorrhoids and other abdominal disorders, and as an abortifacient, whereas pounded young leaves are applied to syphilitic sores.
Trichilia gilletii De Wild. occurs in approximately the same region and closely resembles Trichilia welwitschii, from which it differs in fewer and glabrous leaflets. Its wood is probably used similarly, whereas its bark is used to treat fever and as a purgative, and its seed oil as an emetic.
Trichilia monadelpha is a common understorey tree in lowland evergreen and semi-deciduous secondary forest, up to 650 m altitude, also occurring in forest edges, sometimes in deciduous forest, but then along rivers and in other moist localities.
The 1000-seed weight is about 400 g. When sown immediately after harvest, seeds germinate within 8–15 days, with a high germination percentage. Young seedlings require shade. In Guinea Trichilia monadelpha was planted in full sun, in forests paths and under cover in secondary forest. The best results were obtained under cover, with a mortality of about 40% and a tree height of over 3 m after 6 years, whereas in unshaded conditions mortality was over 70% and the trees were only 1 m tall.
In Ghana stem bark is harvested throughout the year, in pieces up to 5 cm × 2.5 cm, to be used for medicinal purposes, mainly for the treatment of nausea and stomach-ache. The bark is cleaned, dried in the sun and stored at a moisture content below 9%. Packages of 40 kg are transported.
Genetic resources and breeding
Trichilia monadelpha does not suffer from genetic erosion because it is widespread and locally common in secondary forest. Locally, large-scale harvesting the bark may severely reduce populations.
The small size of the bole of Trichilia monadelpha limits its importance on the international timber market, although it is locally important in house building, mainly as piles. Although its bark is a common ingredient of traditional medicinal preparations, little research has been done on its phytochemistry and pharmacological activity.
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Correct citation of this article:
Lemmens, R.H.M.J., 2008. Trichilia monadelpha (Thonn.) J.J.de Wilde. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.