Acacia tortilis (Forsk.) Hayne

Description :

A fast growing small tree 4 to 15 m tall. The crown is often flat, and umbrella like supported by several stems. Foliage is feathery-like and the leaves are compound. Leaves are small 1.25 to 3.5 cm. It is easily identified by its two kinds of thorns: the first type is long straight and white, and the second type is small, brownish and hooked. Deep tap root. The fragrant flowers are white and appear singly or in clusters in the spring. The pods are twisted, yellowish brown and mature in early summer. It can be reproduced both from seed and by vegetative means. It is best reproduced by seed and planted seedlings. Pretreatment of seed by nicking the seed coat, by an overnight soak in water, or a soak in sulfuric acid will increase germination. It is relatively fast growing. Yields of 2 to 4 m³/ha/yr, depending on the site, have been recorded. A 12 year old plantation, in India, produced 54 tons of fuel wood from one ha. Strong coppiced, heavy, dense and dry red colored heartwood has a calorific value of 44000 kcal/kg. Very strong, resilient having coarse and spiral grains.

Distribution :

This tree is native to Africa. It has been introduced in arid and semi-arid areas of Pakistan. It has done well in the Thal desert of the Punjab when it has been planted on sand dunes with hand watering the tree is seeding now. Seeds could be collected for raising nurseries. An intolerant, drought resistant tree that grows on a variety of very harsh, lowland sites that have good drainage. It favors alkali soils and will tolerate salinity. It requires a precipitation zone of 100 to 1000 mm/yr. It prefers an arid to semi-arid, hot, climate with a temperature range of 3 to 45°C. It can tolerate periods of drought of 8 to 10 months. It is relatively free from insect and disease problems. However, its seed may be attacked by insects.

 

Uses :

This tree is adapted to a variety of arid sites and soils. It is best suited to well drained, alkali soils. It coppices readily but can create problems by sending roots into farmers’ fields. It is a good nitrogen fixer and could be used for erosion control on very harsh sites. With care it could be a useful farm forestry tree. Young plants need protection from grazing and frost. Also used as fodder, fuel, gum, honey, land stabilization, poles, and agricultural implements.