The desert tree
The Ghaf is a drought-tolerant tree, able to withstand the harsh desert environment and still remain green and that can live up to 120 years! It can be found on low sand dunes and its presence is an indicator there is water underground.
It is native to arid portions of Western Asia and the Indian Subcontinent, including Afghanistan, Bahrain, Iran, India, Oman, Pakistan, Saudi Arabia, the United Arab Emirates and Yemen. It is an established introduced species in parts of Southeast Asia, including Indonesia.
Prosopis Cineraria inhabits dry, arid areas where annual rainfall averages less than 500 mm (20 in). Rainfall shows considerable variation in the most important areas of its distribution, ranging from 100 to 600 mm (3.9 to 24 in) annually, with a long dry season. In areas of its natural distribution, the climate is characterized by extreme temperatures. Summers are very hot and winters can be severe with frost from December to January. The maximum shade temperature varies from about 40 to 46 °C (104 to 115 °F), while the absolute minimum temperature ranges from 9 to 16 °C (48 to 61 °F). The tree is able to withstand the hottest winds and the driest season, and remains alive when other plants would succumb.
The tree exhibits considerable drought hardiness and it grows on a variety of soils, but grows best on alluvial soils consisting of various mixtures of sand and clay. It is common on moderately saline soils, but can dry out where the soil is too saline.
In India it is one of the chief indigenous trees of the plains of the Punjab, Western Rajasthan and Gujarat and is common in Bundelkhand and the neighborhoods of Delhi and Agra. It is also found in the dry parts of Central and Southern India, occurring in parts of Maharashtra (near Nasik), Andhra Pradesh, Karnataka south of Godavari, Haryana, Western Uttar Pradesh and the drier parts of the Deccan Plateau. Its range extends as far south as Tuticorin.
In general the climatic climax of the Indian Thar Desert is represented by Prosopis Cineraria and Salvadoraoleoides. Prosopis Cineraria occurs on grazing lands, cultivated fallows, barrens and reserved forests, and is found in association with Tecomellaundulata, Capparis decidua, Maytenusemarginata, Ziziphus species, and Salvadora species.
The density of Khejri increases from the Western to Eastern part of the Western Rajasthan. Older and younger alluvial plains are the two habitats preferred by Khejri but it also grows well in sandy undulating plains. Because of its capacity to avail perched water and to absorb moisture from rains through its foliage, it can grow in the extremely arid tracts (100 mm rainfall).