The great Banyan tree in the Indian Botanic Garden, Shibpur, Howrah, W. Bengal is now 232 years old and looks more like a miniforest than a single tree. This indigenous, evergreen tree is known as "BISHAL BOT BRIKSHA" in Hindi and botanically as Ficus benghalensis L., belonging to the family MORACEAE. A large tree attaining a height up to 40 meters and spread enormously with its supporting prop roots from the branches and fixing on to the ground as trunks. Leaves 10-22 cm long, alternate, ovate or elliptic, leathery, entire, obtuse at apex, cordate or round at base. Receptacle 1-1.5 cm across, globose, deep red when ripe, male, female and gall flowers found in the same receptacle.
It is the main attraction for the national and international visitors, scholars and dignitaries visiting the Indian Botanic Garden. It is very much symbolic of the Botanical Survey of India and the name and frame of the Indian Botanic Garden also is largely associated with the existence of this tree. It took birth on the lap of a date palm tree even before the establishment of the present Indian Botanic Garden by Colonel Robert Kyd in 1787. Gradually, it established on the soil after the death of the wild palm. It was growing very majestically with its innumerable prop roots and the main trunk with a diameter of more than 17 meters.
In the year 1803, Lord Valentia visited the Indian Botanic Garden and made a remark in his account of travels that "the finest object in the Botanic Garden is a noble specimen of the Ficus benghalensi,......". Unfortunately, during 1925, the main trunk of the tree was infected with fungal diseases and it was separated to save its numerous branches and prop roots. This tree, by nature, shows peculiar adaptation for producing various prop roots from its different branches for acting as a trunk which uptakes soil nutrients independently without the help of the main trunk. On the other hand, many of these prop roots are trained artificially to the ground in the predetermined areas for adding support to the expanding branches. At present, the tree has spread over 22165-sq. m area with several branches and more than 2800 prop roots. The average girth of some of the prop roots ranges from 20-260 cm.
It is a curio to the botanical world and for which it has occupied a place in the Guinness Book of World Record in 1985. Besides the use of its bark in the treatment of diabetes, leaves for leprosy and milky juice as tonic for health, it serves by providing very cool shades to thousands of visitors during the summer sun. It is a home for various kinds of birds, squirrels and many other micro and macro organisms. The leaves and fruits are very much useful as food and fodder for birds and other animals. Environmentally, it provides many amenities which cannot be measured in terms of its monetary value such as the emission of a large volume of oxygen and absorption of carbon dioxide, mitigation of several air pollutants like dust, sulphur dioxide, oxides of nitrogen, etc., its prop root system helps to bind soil from the surrounding area and maintain the ground water level in a proper condition. The conservationists may find it a living example as to how a single tree can sustain a broad spectrum of biological diversity and ecological security of the surrounding environment.