Bend it like banyan

By TheHindu on 24 Nov 2016

A banyan tree is often called a micro-forest, says Pauline Deborah

Have you ever desired to have India’s National Tree planted in your courtyard? The mighty banyan is designated as the National Tree of India. The idea of planting a banyan could be considered weird or a wrong choice in urban gardens and can be easily shrugged off or shelved away. Why would any landscapist recommend this outsized and expansive species which is a total misfit in cities with rapidly shrinking green spaces?

For those who have grown up in metro cities and concrete jungles, the name banyan would mean a large, spreading tree in a rural setup where local panchayats take place for the dispensation of justice. This is the imagery that is more often portrayed in movies or the mystical swinging in its aerial roots.

Ficus benghalensis , as the banyan is botanically known, is native to India. The specific name benghalensis , commemorates Bengal, where the venerated great banyan grows inside the Acharya Jagadish Chandra Bose Indian Botanic Garden at Kolkata. Banyan takes the name from the Sanskrit word Banias which literally means traders. Since they sold their merchandise under the shade of this tree during the colonial period, the tree was christened as banyan by the British.

Aerial roots

Banyan is a large, spreading tree which requires a lot of space around it. The most striking feature of this tree is the pendulous, strong, aerial roots which hang in clusters from the upper parts of the branches. It reaches the ground much below from its source of origin and reach the ground for anchorage, soon turning into a great pillar of strength and as an accessory trunk, distancing itself from the mother trunk. Therefore the tree actually appears like an agglomerate of many trees. But actually it’s a single tree! The roots of banyan, both aerial and underground, provide a dual fixative assurance for this widely stretching species. Sometimes the aerial roots are tightly knitted and knotted, looking haggard, which probably prompted Rabindranath Tagore to write the lines ‘ O you shaggy-headed banyan tree standing on the bank of the pond ….’

Though it is a deciduous tree, the period of its leaf fall is not conspicuous and therefore the tree renders the appearance of an evergreen species. It is a shade yielding tree and offers a great respite during summer because of its intact foliage during that time. There is a rapid decline in banyan population in cities because of rampant urbanisation. Moreover people in cities prefer small ornamental trees that would occupy minimal space in the garden.

Banyan is celebrated as a sacred tree and is not axed because of the popular belief that it brings prosperity and goodness to the neighbourhood. Banyan trees that are many years old are considered as heritage specimens that deserve protection from vandalism and massacre.

Though banyan is a high and mighty species, it is obligatorily dependent on most humble and unobtrusive organisms for its two survival processes - pollination and dispersal. Pollination is facilitated by the tiny fig wasps and dispersal of seeds is made possible by frugivorous birds and bats. The fruits of banyan, popularly known by the name fig, are actually a congregation of tiny flowers inside a receptacle, known as a hypanthodium. The tiny, female wasp forcefully navigates itself into the fig by squeezing and struggling through a small opening at the tip, and in the process loses its fragile wings. Once inside, it lays its eggs and also deposits the pollen that it collected from its earlier birth site in another fig. After this it dies and later digested by the enzymes in the fig. Meanwhile the larvae develop inside the fig.

After a while, the wingless males fertilize the winged females and also chew a channel for the females to fly out of the fig with the pollen dusted on its body, thus completing their two vital duties. Now the females go in search of another young unripe fig to not only complete its life cycle but also to ensure pollination.

Intricate process

This is a very intricate, obligate and a mutualistic relationship where the fig gets pollinated by the wasps and the figs provide a safe niche and food for wasps and their young ones. Once the wasps fly out, the copious figs ripen, turn red and produce a fruity smell, signalling the fact they are ready for dispersal by birds and bats, thus facilitating another symbiotic association.

The birds gorge themselves with the edible figs and excrete the undigested seeds further away, thus ensuring dispersal of the seeds and another generation of figs.

Like most other trees, banyan cannot afford to drop the seeds straight from the tree and germinate. This is because it might to lead to competition between the parent plant and the young one for resources like space and sunlight.

Keystone species

A single banyan tree can be allegorically referred as a micro-forest, since it supports a variety of wildlife such as birds, wasps, bats and therefore is labelled as a keystone species. Banyan sustains many a wildlife by offering food, shelter and shade.

Closely observing the flurry of activities in the banyan tree during fruiting season is an exciting experience by itself, especially for children who are passionate about recording facts for their assignment in natural science.

Damage to buildings

Banyan usually starts its life as an epiphyte. The birds drop the seeds in the crevices of buildings or while perching on another tree. Being a calciphile, it can easily establish itself in calcium-rich surfaces and therefore grow very aggressively on walls and buildings. These have to be detached very early, so that they do not cause further damage to buildings.

If the seeds are dropped on the branches of another tree, it will germinate unassumingly just like another plant, but slowly entangle the host plant, completely strangulating it at the end. Neem and Palmyra are the most usual victims of such parasitic behaviour.

Banyan tree has been recorded in the Guinness Book of Records for being the widest tree in the plant kingdom. The bonsai of banyan is quite popular because of its easily amenable nature and is a ready choice for bonsai gardens.

Is it possible to grow a banyan in your home garden? Yes, if you are in a house with a lot of open space around or if you are working in a organisation that encourages tree planting and also has lot of free space.

Banyan saplings are available in plant nurseries.

The bonsai of banyan is quite popular because of its easily amenable nature and is a ready choice for bonsai gardens

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