Ber/Bair/Borari is a fruit bush/tree of Thar Desert, mostly found in plan areas as well as on sand dunes. The scientific name of Bair is Zizphus mauritiana and belongs to class magnoliopsida, order rosales and family Rhamnaceae of Plant Kingdom.
There are two types of beer/ber/bar are found in Thar Desert 1. Wild Jujube (small beer) 2. Apple Beer, both are very testy and nutrient fruit.
According to the habitat of Ber Tree, it is amazing in its potential to tolerate in drought as well as water-logging. 
Beri might grow in dry tropical and sub-tropical climates with adequate soil moisture, with normal to high rainfall as well as temperature up to 50oC.
According to scientific studies, the tree grows best on sandy loam, neutral or slightly alkaline and the ber/bair tree flourishes in high pH soils. When the plant reaches on about 4-5 feet height it starts produce fruit and seed. Mostly ripen in February & March every year but some plants ripen in March, some in October too.
Leaves of the tree are favorite fodder of goat. The leaves have a very high nutritive value.
Reference: Information about Nutritional Value collected form Wikipedia link is available in Photo.
Verry Good
Verry Good taste