Prota 7(1): Timbers/Bois d’œuvre 1
Ann. Mus. Natl. Hist. Nat. 4: 90 (1804).
Tiliaceae (APG: Malvaceae)
Bastard brandy bush, false brandy bush, donkey berry, two-coloured grewia, white raisin (En). Greuvier, grévier bicolore, nogo blanc (Fr). Mfukufuku, mkone, mkole (Sw).
Origin and geographic distribution
Grewia bicolor occurs widely in the drier parts of tropical Africa, throughout the Sudano-Sahel zone from Senegal to Eritrea, Ethiopia and Somalia, and through eastern Africa southward to Namibia, Botswana, South Africa and Swaziland. It is also recorded from coastal Benin and Togo and occurs in Yemen, Saudi Arabia and India.
The wood of Grewia bicolor is used in house construction (poles, beams) and made into a range of articles including tool handles, herding staffs and walking sticks, bows, arrows, spear shafts, knobkerries and clubs, pegs, rakes and saddle frames. It is used for carving and in Kordofan (Sudan) the wood is hollowed out to make bowls and boards for the ‘kalah’ game, and the stems are made into picture frames. In Burkina Faso sticks are woven into baskets. The wood is also used for firesticks, as fuel wood and made into charcoal.
The sweet, mealy fruit pulp is eaten fresh, or dried as candy. Juice from the fruit is drunk fresh, added to porridge, fermented into beer or distilled into liquor. The mucilaginous leaves and fibres from the leaf are used as binding agent in sauces. Fresh leaves are made into a kind of tea. In Burkina Faso the bark or leaf fibres are used in the preparation of sorghum beer to make it clean and to remove bitterness. The bark is also used to clarify muddy water. The bark fibre of Grewia bicolor is made into cordage and used for weaving. The fresh and dry leaves, young stems and fruits serve as forage for domestic animals. The leaves and ash from burnt leaves are sometimes used as soap and for cleaning garments. The tree is also used as an ornamental, as a shade tree and as bee forage.
Grewia bicolor has a wide range of applications in African traditional medicine. The bark is used as a vermifuge, diuretic and laxative, and to treat boils and sores, intestinal inflammation and syphilis. In Senegal a macerate or decoction of the bark is credited with both inebriating and tranquillizing effects, and is also taken to counter fatigue. In Kenya the bark is applied in case of itching, while in Tanzania it is chewed and put on wounds as a bandage. The wood is credited with anthelmintic activity. In Côte d’Ivoire a decoction of the leaves is drunk and put into baths against pain in the chest, after which sap from pounded roots is rubbed on the patient. In East Africa a cold infusion of the root is drunk to treat anaemia, chest complaints, cold, diarrhoea, snakebites, mental illness, hernia and female infertility. In Sudan a poultice of the root is applied on pustulent skin lesions, and the root is taken as a tranquillizer. A decoction of the root is given in case of a delayed afterbirth. In Niger the powdered root bark is applied on burns, and in Mali the juice or a decoction of the inner bark of the roots is applied on wounds. In Namibia a syrup prepared from the roots is rubbed onto swollen legs. The plant is also used in veterinary medicine, e.g. to treat stomach problems.
Production and international trade
The wood of Grewia bicolor is not traded in the international market.
The wood of Grewia bicolor is hard and strong; young branches have good elastic properties.
Per 100 g dry matter the leaves contain: crude protein 16.7 g, fat 4.7 g, nitrogen-free extract 48.4 g, crude fibre 21.5 g. Per 100 g dry matter the fruit contains: crude protein 4.9 g, fat 3.5 g, carbohydrate 74.3 g, crude fibre 13.0 g, Ca 920 mg, Mg 200 mg and P 144 mg (Baumer, 1983). The fruits are sweet but astringent.
The bark and other plant parts contain farnesol, which has sedative activity and is antagonistic to the stimulant effect of caffeine; farnesol also enhances the effects of barbiturates. A petroleum ether extract of the root contained the triterpenes lupeol and betulin, and triterpene esters. A methanol extract yielded the alkaloids harman, 6-methoxyharman and 6-hydroxyharman. A methanol extract of the root has shown antibacterial activity against Staphylococcus aureus, Bacillus subtilis , Escherichia coli and Pseudomonas seruginosa and causes a strong contraction of the isolated rat uterus which can be blocked by methysergide. The harman alkaloids may be linked to its use as a tranquillizer.
Shrub or small tree up to 10(–14) m tall, producing suckers and branches from the base of the main trunk; bark smooth when young, later dark, deeply fissured and scaly, with many lenticels; young branches greyish to brownish hairy. Leaves alternate, simple; stipules linear-lanceolate, 4–12 mm long; petiole 2–6 mm long, greyish to brownish hairy; blade usually elliptical, rarely oblong or ovate, 1–12.5 cm × 0.5–6 cm, base rounded, often slightly asymmetrical, apex acute to obtuse, margin minutely toothed to entire, 3-veined from the base, green and glabrous to minutely hairy above, whitish hairy beneath. Inflorescence an axillary cyme, 1–3 together, 2–3.5 cm long, (1–)2–3-flowered; peduncle 4–13 mm long; bracts ovate to lanceolate, 2–5 mm long, caducous. Flowers bisexual, regular, 5-merous, sweet smelling; pedicel 5–14 mm long; sepals 6–14 mm long, greyish or brownish green hairy outside, glabrous and yellow inside; petals obovate to oblong, 3–9 mm long, bent back over sepals, apex acute to emarginate, bright yellow to orange; stamens numerous, 6–7 mm long; ovary superior, c. 1.5 mm long, 2–4-celled, densely hairy. Fruit a drupe, usually 2-lobed, lobes 4–7(–11) mm × 4–8(–11) mm, more or less glabrous or with scattered minute stellate hairs, orange turning purple-black; endocarp hard, woody, reticulate.
Grewia comprises about 150 species, distributed in the tropical and subtropical parts of Africa, Asia and Australia. Grewia bicolor is extremely variable, and it hybridizes freely with Grewia monticola Sond.
Other Grewia species used as sources of timber in Central and East Africa include Grewia ferruginea Hochst. ex A.Rich., Grewia louisii R.Wilczek, Grewia microthyrsa K.Schum. ex Burret, Grewia pinnatifida Mast. and Grewia plagiophylla K.Schum. The wood of Grewia ferruginea, distributed in Sudan, Eritrea, Ethiopia and Kenya, is used in construction and for farm tools; it is also used as firewood. The fruits are eaten, the leaves serve as fodder and the bark is made into rope. The root and a paste of the bark are recorded as being used as an anthelmintic; the bark is used as a scabicide. The wood of Grewia louisii R.Wilczek, occurring in DR Congo, is used in construction and for firesticks; the fruits are edible and dried and powdered they are used against cough. The stems of Grewia microthyrsa (Lebombo raisin or sand raisin), distributed in southern Mozambique and South Africa, are used for spear shafts and in the construction of huts and fences. The fruit is edible and the plant is browsed by livestock. Root macerations are taken to treat infertility and as an aphrodisiac. The branches of Grewia pinnatifida Mast., distributed in DR Congo and Gabon, are made into bows and ropes, and the dry wood is used for firesticks. The wood of Grewia plagiophylla, distributed in Somalia, Kenya and Tanzania, is used for poles, posts, tool handles, bows, arrows, knobkerries and for carving. The bark is a source of fibre. A root decoction is taken to treat kidney problems and gonorrhoea; an infusion of the leaves or leaves and roots is drunk to treat stomach-ache. Fibres from the plant are immersed in water to produce a foam to wash eyes affected by irritating substances. To treat mental illness vapours of a leaf decoction are inhaled and a decoction of the leaves and roots is taken.
Grewia bicolor grows slowly. In areas with a marked dry season, flowers are produced in the rainy season and leaves are shed during the dry season. In Kenya it is recorded as flowering throughout the year, peaking in November–January. In Burkina Faso the density of Grewia bicolor taller than 1.5 m was 47 trees/ha in an area with average annual rainfall 486 mm and average annual temperature 29–30°C.
Grewia bicolor is drought-resistant and mainly distributed in areas with an average annual rainfall of (200–)400–900 mm. It occurs up to 2000 m altitude, in dry woodland, thicket, Commiphora-Acacia bushland, wooded grassland, and along rivers and streams. It is often found on sandy and rocky soils and red clay soils.
Grewia bicolor is normally collected from the wild. It can be propagated by seed, wildlings, cuttings and root suckers. Germination is improved by mechanical scarification (piercing or nicking) or soaking in cold water for 12 hours. The 1000-seed weight is 65–110 g. Dried seed can be stored for over one year at room temperature, provided it is protected against insect attack. Strike rates of cuttings tend to be low, although heel cuttings can have a success rate of 60%. Grewia bicolor is easy to grow in the nursery and usually shows good survival after transplanting. It coppices and prunes well. The sun-dried fruit, that looks like a raisin, is sometimes stored to be used in the dry season. It stores well.
Genetic resources and breeding
In view of its wide distribution, Grewia bicolor does not seem to be threatened by genetic erosion, although it is locally considered vulnerable, e.g. in Burkina Faso.
Grewia bicolor is a veritable multipurpose tree, yielding a range of useful products, and it therefore seems a good candidate for community forestry projects. However, more research is needed on appropriate propagation and management practices and possibilities for selection of improved genotypes. In view of the normally small size of the tree, its timber is unlikely to become important as sawn wood.
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Correct citation of this article:
Brink, M., 2007. Grewia bicolor Juss. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
bark and slash
obtained from Zimbabweflora
obtained from Zimbabweflora