Common Name: African Birch

General Information

African birch is an evergreen shrub or small to medium-sized tree with an open crown of gracefully drooping, pubescent branches; it can grow up to 15 metres, occasionally reaching 30 metres. The straight, slightly grooved bole usually branches from low down, it can be up to 100cm in diameter[].
A mulltipurpose tree that is very important to the local economy. It provides an edible gum, various medicinal uses and a range of other commodities, many of which are sold in local markets. The plant is highly esteemed as a source of dye material which is much used in traditional crafts in Africa[]. In Burkina Faso it is a highly esteemed and respected holy tree, named ‘siiga’, meaning ‘the soul’[]. In Benin the tree is occasionally planted near villages for its dye and in Burkina Faso and Mali plantations have been planned[]. The tree yields a valuable timber, known as 'kane' in the trade, and so has been widely exploited commercially[]. It is often grown for its ornamental value and in drier regions becomes an effective shade tree[]..

Known Hazards

None known

Botanical References

Range

Tropical Africa - Senegal to Eritrea and Ethiopia, south to DR Congo.

Habitat

Found from the driest savannah to the wetter forest borders, in wooded grassland and bushland and on riverbanks[]. Often grows gregariously on fertile soil in moist situations, from sea-level up to 1,900 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	15.00 m
Growth Rate	Slow
Cultivation Status	Semi-cultivated, Ornamental, Wild

Cultivation Details

A plant of the African tropics, from lowland to moderate elevations, able to grow in semi-arid to much moister areas where annual rainfall can range from 200 - 1,200mm[].
Prefers a moist, fertile soil[]. Succeeds on a range of soils, including compact clays[]. Prefers an acid pH[].
A slow-growing tree, it flowers year-round but most abundantly at the beginning of the rainy season[]. The flowers have a strong sweet smell[].
The tree can be pollarded and has some ability to coppice[].
It is very sensitive to fire[, ].
In regions where African birch is collected, the harvesting contributes to the growing scarcity of the tree populations, which is exacerbated because little rejuvenation appears to be taking place[]. The tree used to occupy whole forests on fertile soils but it is becoming rarer because land is being cleared for agriculture, wood is collected for timber and fuel and the seeds are difficult to germinate[].

Edible Uses

An edible gum is obtained from the bark[]. Fairly soluble in water, it is chewed and, in northern Niger, it is considered the best chewing gum substitute for gum arabic[, ]. It contains 22% uronic acid. It is of good viscosity and is usable as a substitute for or adulterant of gum-arabic[].
A cold water infusion of the gum is considered a palatable beverage[]. A decoction is given to a new-born baby to drink[].

The fruit and the calyx are used in the preparation of sauces or to make a tea[].

Tender young leaves - cooked and eaten as a vegetable[].

Medicinal

The bark, leaves and roots are all used in traditional medicine usually in the form of decoctions[]. They have antimicrobial and anthelmintic activity and are usually taken as decoctions[]. Extracts of the stem and root bark and of the leaves have shown antifungal activity against a number of pathogenic fungi. Moderate antibacterial activity of the bark was also demonstrated[]. Extracts of the plant have exhibited in-vitro activity against chloroquine-resistant Plasmodium falciparum strains[].

A decoction of the leaves or leafy twigs is used against yellow fever, jaundice, different kinds of hepatitis, common cold and headache.
Externally, a leaf decoction is applied against haemorrhoids and skin diseases.

The root-bark is considered to be aphrodisiac and stimulant[]. In some regions the bark is used as a febrifuge in hot lotions and infusions[].
The powdered bark and a bark decoction are used externally to treat wounds, eczema, psoriasis, anthrax, carbuncles, boils and several kinds of ulcers. The bark decoction is also known as a muscular tonic. The bark and the exuding gum have been shown to prevent and cure dental caries and toothache and are commonly used in Africa[].

The gum obtained from the bark is laxative[]. It can be used in pharmacy as an emulsifying agent[]. The bark itself is chewed to obtain the gum[].

The fleshy roots are used against labour pains[]. The pulped roots are applied to sores to promote healing, and to accelerate wound healing[, ].

The seeds have a wide bactericidal and fungicidal activity in humans and animals[].

Agroforestry Uses:

The tree is planted in Eritrea to stabilize river banks[].
Within its native range it is a pioneer species on open forest clearings[]. However, the tree has very slow initial growth and is very sensitive to bush fires, which somewhat limit its usefulness[, ]. When grown gregariously it effecively kills out grass[].

Other Uses

The leaves are rich in tannins and are used to dye cloth a yellow colour[]. In West Africa, they are commonly used in the oldest African traditional dyeing process of cotton textiles known as 'basilan'[].
Dyeing with the leaves of this plant has even become a full-time occupation for many people[].
The bark, and roots are also a source of tannins and dyes[, ].

The ash of the leaves, the bark and the wood are used as mordants to improve the fastness of many other dyes and in the indigo dyeing process to maintain the necessary alkaline pH[, ].
The wood ash is used as a lye in washing clothes and as a basis for making soap[].

The damaged bark exudes a partially soluble gum which contains 22% uronic acid. It is of good viscosity and can be used as a substitute for or adulterant of gum-arabic (Senegalia species). It is used in various ways, including for beating cloth; to make ink more viscous; as an adhesive; medicinally; and for food[, , ].

In Ghana and Nigeria the roots are used and traded as chewing sticks[, , ]. The chewing sticks have shown strong activity against a wide spectrum of bacteria, including some contributing to tooth-deterioration[].

The heartwood is a dark, dull brown, streaky, becoming almost ebony-black; it is distinctly demarcated from the wide band of whitish yellow sapwood. The texture is fine; the grain wavy or interlocked. The wood is heavy and hard; it is not durable in contact with the soil, but is resistant to the attacks of termites and insects, though not of marine borers. It is extremely resistant to preservatives. It seasons rapidly, but with some distortion. The wood is moderately easy to saw, but difficult to plane, mortise and bore; it finishes and polishes well and is easy to turn and glue, but nailing is difficult. It is much used for piles and rafters in house construction, for agricultural implements, tool handles and occasionally in cabinet making. It is a favoured wood for use in carving[, , ].
The wood is an excellent fuel and yields good charcoal[, , ]. In the whole Sahel region fuel has become so scarce that even these useful trees are being sacrificed[].

Propagation

The seeds are very small and soon lose their viability (within 6 months); in addition, their germinating capacity is rather low, with only 10 - 15% of the seed proving to be viable[, ]. The germination of the seeds takes a long time and seedlings are not easy to obtain.

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