"Leucaena's salt tolerance is effective only along shore lines where calcium levels are high. As with many other plant species, the tolerance of "salt" is a complex subject, for salt can represent a great assortment of chemicals. Generally, the major difference is seen when comparing coastal salinity (highly calcareous) with inland evaporative salinity (e. g. Salt Lake), which is usually not calcareous. Leucaena tolerates the former, not the latter. Calcareous refers to soils with high calcium content, primarily coral-derived soils with accompanying high pH. Arid regions naturally have areas of high salinity due to evaporation and salt accumulation; such soils are often lower in calcium, higher in sodium, and thus more toxic to plants. A few nitrogen fixing trees do handle the salty non-calcareous soils. The best work with these is at CAZRI (Central Arid Zone Research Institute of India) in Jodhpur, India.