Agroforestree Database

Local names:
 Afrikaans (kameeldoring), English (giraffe thorn,rubber thorn tree,camel thorn), Hindi (odassithai,jala,karodei), Lozi (muhoto), Ndebele (umdwadwa,umwhohlo), Nyanja (mkunku,nyafungo), Somali (jifjif,sarmaan), Tongan (mungoshia), Tswana (mogotlho)

A large, spreading tree, 9-10 (max. 18) m high, branching about 2 m above the ground; occasionally a shrub barely 2 m tall; crown rounded, dense, spreading up to 18 m; branches drooping at the ends; sapwood yellow and the under bark  is reddish; bark dark greyish-brown to blackish, rough, fibrous, fissured, often flaking off in thick, woody strips when old; young twigs shiny, purplish or reddish, without hairs, distinctively zigzag shaped; taproots, long.

Leaves with 2-5 pairs of pinnae, each bearing 8-15 pairs of bluish-green leaflets 4-10 x 1-4 mm, remaining conspicuously green in the dry season; thorns dark brown, later grey or whitish, in pairs at the nodes, stout and straight, 1-5 cm long, at right angles to each other and pointing in the opposite direction to the previous pair; base of older thorns often inflated into an enlarged ant-gall 0.5-2 cm wide.

Inflorescence consists of a ball of bright golden yellow, solitary or clustered, fragrant flowers.

Pods green, broad, large, 1.3-2.5 cm thick but flattened, spongy within, half-moon shaped, 6-13 x 1.8-6.5 cm, curved through to 90-180 degrees, semi-woody, indehiscent, covered in dense grey hairs and containing hard, brown seeds that lie in several rows; some pods thin, round and long.

The generic name ‘acacia’ comes from the Greek word ‘akis’, meaning a point or a barb. The scientific name ‘erioloba’ is Latin for ‘half-moon shaped’, referring to the shape of the pods.

Ecology

A. erioloba is frost and drought resistant. It is the dominant tree on the desert plains, sometimes occurring in beds or on the banks of rivers. Trees occurring outside this favoured habitat are usually stunted. Young plants require large amounts of light.

Native range
Angola, Botswana, Mozambique, Namibia, South Africa, Zambia, Zimbabwe

Tree management

A. erioloba, which bears valuable pod crops, can be grown on perennial grassland at a rate of 5-10 trees/ha without damage to the grass yield. It is advisable that the tree be grown in the habitat to which it is naturally adapted. 
The number of pods/tree is 25-1 200, and each pod weighs 7.4-30.2 g. The total weight of pods produced is about 600 kg/ha, with an annual yield of pods from a natural stand of mature trees being conservatively estimated at 1-2 t/ha. Cattle pass large quantities of seeds (about 50 seeds/dropping) in their dung. This facilitates bush encroachment by A. erioloba and other acacias with indehiscent pods. It is therefore included among 1652 taxa shown to be weedy in certain situations in southern Africa. It competes with other plants for space, light and nutriment. This species is valued throughout its range for its products and services and is rarely the subject of eradication measures. Two chemicals that are selective of woody species, tebuthiuron and ethidimuron, successfully control the species should it become a problem. Fire causes young A. erioloba trees to coppice and well-established, scrubby trees may thickening up.

Seed storage behaviour is orthodox; seeds retain their viability for many years even at room temperature. Bruchid larvae within the seed continue to be active after the seed has been extracted and stored. The adults or larvae of some species emerge and may even re-enter the exit holes to lay eggs or to produce a 2nd generation of larvae that feed on the seed. Storage at temperatures near freezing point reduces bruchid beetle activity, and subzero temperatures of -20-30 deg. C may kill the larvae without damaging the seed. On average there are 22 000 seeds/kg.

A. erioloba is frost and drought resistant. It is the dominant tree on the desert plains, sometimes occurring in beds or on the banks of rivers. Trees occurring outside this favoured habitat are usually stunted. Young plants require large amounts of light.

Natural and artificial regeneration from seed is poor, even after presowing treatment, but trees coppice and sucker fairly readily. Seed germination rates are improved by planting seeds along with dung from cattle that have been feeding on the pods. This is because bruchid larvae that normally infest seeds are usually killed during their passage through the gut of a herbivore. Seedlings are best sown singly in containers and have to be transplanted quickly as the taproot develops rapidly. They should be planted out when 46 cm or more in height and should be watered for the 1st few months, after which they become drought resistant.

Poison:  The prussic acid that is sometimes present in the pods and foliage may poison animals.

Erosion control:  A. erioloba has been planted to help in sand dune stabilization, thus is useful in combating soil erosion.

A. erioloba produces a good quality, edible gum. Seeds have been used as a substitute for coffee.

Leaves and pods are eaten by livestock and are a valuable source of fodder in the dry season. Pods are highly nutritious, their feeding value matching that of legume hay; a noticeable increase in the milk yield of cows that have eaten them has been reported.

Apiculture:  Flowers are a source of nectar for honeybees.

A. erioloba is a source of firewood for much of the Kalahari region in southern Africa.

Timber:  The wood is hard, durable and resistant to borers and termites. The heartwood is dark purple and has been used for poles, especially for the center posts for houses, mine props, wagon building, utensils and even machinery (but the machinery must be kept well oiled). Roots are used as a substitute for reeds to make flutes.

Shade or shelter:  Mature trees provide shade in desert areas and the wood is used for construction of enclosures in southern Africa.

Medicine:  Gum from the tree is used as a cure for gonorrhea. Bark is burned, crushed and used for relieving headache. Pods are ground into a powder to treat ear infections. Roots are used as a cough remedy.

Ornamental:  The beautiful tree is suitable for planting in amenity areas.