Prota 7(1): Timbers/Bois d’œuvre 1
Bot. Jahrb. Syst. 30: 75 (1901).
Mimosaceae (Leguminosae - Mimosoideae)
Purple-leaved albizia, purple-leaved false thorn (En). Muiando (Po).
Origin and geographic distribution
Albizia antunesiana is widespread, from eastern DR Congo, Rwanda, Burundi and Tanzania south to Namibia, Botswana, Zimbabwe, Mozambique and South Africa.
The wood of Albizia antunesiana is used for heavy construction, joinery, furniture, boat building, plywood, drums and implements in Zambia and Zimbabwe. It is one of the woods preferred by the woodcarving industry in southern Zimbabwe. The wood is suitable for cabinet work, interior trim and railway sleepers. It also serves as firewood. The roots have numerous uses in traditional medicine. They are applied externally to treat sore eyes, cuts, ulcers, pneumonia, painful and swollen legs, and internally as an infusion or decoction to treat sore throat, tonsillitis, tuberculosis, gonorrhoea and other sexually transmitted diseases, abdominal pains, depressed fontanelle in infants and infertility in women, as an aphrodisiac, and to prevent abortion. A bark infusion is taken to treat constipation and applied externally to cuts, whereas crushed leaves are used as an enema for their purgative action and as a dressing to treat oedema of the legs. The bark has been used for tanning, and the flowers are a source of nectar for honey bees.
The heartwood varies from pale brown to purplish brown, sometimes darker striped, and not distinctly demarcated from the up to 6.5 cm wide, whitish sapwood. The grain is irregularly interlocked, texture moderately coarse.
The wood is moderately heavy, with a density of 640–785 kg/m³ at 12% moisture content. It dries slowly, but with little degrade. Shrinkage rates from green to 12% moisture content are 1.3% radial and 2.0% tangential. Once dry, it is stable in service. The wood saws and works well, but blunts tools rather rapidly. Surfaces may tear because of interlocked grain; a cutting angle of 10° is recommended for planing and low speeds are needed in moulding. The wood may split upon nailing. It does not turn well, but mortises, peels and slices satisfactorily. The sawdust causes irritation to nose and throat. The wood is considered durable and resistant to termites. It is highly resistant to impregnation by preservatives.
Roots of Albizia antunesiana showed significant in-vitro activities against the tapeworm Hymenolepis diminuta (‘rat tapeworm’) and the trematode Schistosoma mansoni, causal agent of schistosomiasis.
Small to medium-sized deciduous tree up to 18(–25) m tall; bole usually short and branchless for up to 5 m but sometimes up to 12 m, straight or twisted, up to 75 cm in diameter; bark surface grey to brown, smooth or rough and reticulate, inner bark with reddish exudate; crown flattened, umbrella-shaped; young twigs glabrous or very shortly hairy. Leaves alternate, bipinnately compound with 1–3(–4) pairs of pinnae; stipules awl-shaped, caducous; petiole 4–8 cm long, grooved above, glabrous, near the base at upper side with a sessile gland, rachis 8–14 cm long, glabrous or sparsely pubescent; leaflets in (3–)4–8(–9) pairs per pinna, almost sessile, obliquely rhombic-ovate to elliptical-oblong, up to 5(–7) cm × 2.5(–4) cm, rounded to slightly notched at apex, glabrous, distinctly glaucous below. Inflorescence an axillary head on 2–11 cm long peduncle. Flowers bisexual, regular, 5-merous, greenish yellow; pedicel up to 2 mm long; calyx 3–5.5 mm long, with long tube toothed at apex, pubescent outside; corolla 5–11 mm long, pubescent outside; stamens numerous, 1.5–3 cm long, united at base, with white filaments; ovary superior, gradually tapering into an up to 3 cm long style. Fruit an oblong, flat pod 12–23 cm × 2.5–5 cm, almost glabrous, indistinctly transversely veined, pale brown when ripe, opening with 2 papery valves, c. 8-seeded. Seeds lens-shaped, 7–9 mm in diameter.
Albizia antunesiana trees usually flower in August–November and fruits are ripe in April–September. The pod valves with seeds still attached are spread by wind.
Albizia comprises about 120 species and occurs throughout the tropics. Approximately 35 species are found in continental Africa and about 30 in Madagascar. It is characterized by the head-like inflorescence, with 1–2 central flowers modified, functionally male and having a larger, nectar-producing staminal tube. Molecular analyses showed that Albizia is heterogeneous, and a revision of the genus is needed.
Albizia antunesiana occurs in deciduous woodland and wooded grassland at (250–)900–1700 m altitude.
Propagation can be done by seed. Seeds should be collected before the pods dehisce, which makes collection difficult. Wildlings are sometimes collected for planting. Planted trees can be managed by lopping and pollarding.
Genetic resources and breeding
There are no indications that Albizia antunesiana is threatened by genetic erosion. However, the common practice of harvesting the roots for traditional medicine may severely reduce populations of the species locally.
Although the wood of Albizia antunesiana is of excellent quality, it is of little economic importance because of the often small size and poor shape of the bole. However, trees of good stature do exist and planting experiments are desirable to evaluate possibilities as a timber-plantation tree. It is surprising that such a well-known medicinal tree has hardly been tested on its pharmacological activities.
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Correct citation of this article:
Lemmens, R.H.M.J., 2007. Albizia antunesiana Harms. 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 Zimbabweflora
obtained from Zimbabweflora