Prosopis juliflora (Swartz) D.C.

Description :

An almost evergreen, thorny, shrub or small sized tree 10 m tall. The crown is open and stem diameters of 20 cm have been reported. Foliage is feather-like, and the leaves are compound up to 1.8 cm long. Leaf fall occurs for a short period before flowering. The flowers are small, greenish yellow, arranged in small, dense bunches, and appear between March and June. The pods are fleshy, flat, 16 to 23 cm long and contain on the average 10 to 18 seeds. The straw-colored pods mature between May and July. A number of insects attack it, but they are of little significance. It is reproduced both from seed and by vegetative means. The seed can be stored for long periods. Pretreatment of seed by nicking the seed coat, or a water or acid soak will speed germination. Yield of 3 to 5 m³/ha/yr has been recorded. On favorable sites it produces 50 to 60 tons/ha biomass on a 10-year rotation. Because of its seed habit it can become a weed problem thus care should be taken so it does not escape cultivation. It is considered a noxious weed in parts of Pakistan. Heartwood is rich brown, sometimes red with spiral grains. Dense with a specific gravity of 0.70, and a calorific value of 4500 kcal/kg.

Distribution :

The tree is native to the West Indies, the southwestern United States, Central and South America. In Pakistan it is found in the dry plains and hills of the Sindh, Punjab, Balochistan and KP. An aggressive intolerant tree that grows on a variety of dry sites including most soils from clays to sands. It also does well on highly alkaline sites (ph 9.8). It requires a precipitation zone of 150 to 750 mm/yr and is considered very drought hardy because of its large tap root and extensive root system. It prefers a hot arid, semi-arid to sub-tropical climate with a temperature range of -2 to 45°C at elevations up to 1200 m. It is fairly frost hardy, and grazing is not a problem since cattle avoid it. Once established it is very difficult to eradicate.

Uses :

This tree is adapted to a variety of sites and soils, coppices readily, and is a good nitrogen fixer. It can be used on saline, sodic sites. Also used as fodder, fuel, nitrogen fixing, poles and construction, agricultural implements, apiculture, furniture, and soil stabilization purposes.