The city of Vadodara is named after the banyan, while the township of Auroville was founded under a banyan tree. Bal Samand palace in Jodhpur has a giant banyan with a big colony of fruit bats. It is believed to be 550 years old. Adyar in Chennai has a 450-year-old banyan tree. A great banyan tree in the Kolkata Botanical Gardens and the Big Banyan Tree of Bengaluru are other centuries-old heritage trees that have witnessed many changes in their surroundings.
Thimmamma Marrimmanu in Andhra Pradesh, believed to be close to 600 years old, is considered the largest banyan in the world, spreading over 19,000 square metres. The tree is worshipped by couples praying for a child. Just to give you an idea of what the size of the tree means—20,000 people can gather comfortably under the shade of this one tree. In fact, thousands of people collect under this tree during its jatra (annual festival). Pliny was right in saying that entire troops of horsemen could be concealed under a single tree’s branches.
These historic banyans have witnessed our changing pasts and have been commemorated in poems ranging from Milton’s Paradise Lost, to Rabindranath Tagore’s The Crescent Moon. If they could speak, they would have much to narrate. The Brahma Purana pays tribute to the remarkable capacity of an immortal banyan tree, the Akshaya Vata, to survive the pralaya (the great flood). The sage Markandeya, says the Brahma Purana, found a banyan tree surviving in the midst of devastation, where he was blessed with the sight of Vishnu as a baby. The Akshaya Vata is believed to be located variously in Allahabad, Varanasi and Gaya. An Akshaya Vata in Allahabad is found at the confluence of the Ganga and Yamuna. The tree is so old that it was described by Hiuen Tsang, the Chinese pilgrim who visited India over 1000 years ago. It is now housed inside the Allahabad Fort and protected by the Indian Army, but visited by thousands of pilgrims during the famous Kumbh Mela.
In more recent times in Mumbai, a large banyan in Horniman Circle, in the old Fort area, has played witness to a fast-changing economic and cultural landscape. The tree has witnessed the transformation of Bombay from a rustic scene with grazing cattle to an urban landscape with British gardens, and later to the bustling skyscrapers of modern Mumbai. In 1855, twelve Indian cotton merchants got together to found the iconic Bombay Stock Exchange under this tree. The stock exchange later moved to another banyan tree, on the nearby Meadows Street. Now considered the world’s fastest-trading stock exchange, valued at over 2.3 trillion dollars, who would think that it began under a simple banyan tree?
Banyan(Ficus benghalensis)
Description: Full-grown trees have a majestic, dense canopy with aerial roots that drop to the ground and develop into trunks. Bark is relatively smooth, greyish-brown in colour and can appear silvery.
Flowers: Not visible as they are tiny and enclosed inside the fruit (fig).
Fruits: Figs are spherical in shape, downy and turn red on ripening.
Leaves: Oval-shaped leaves with a leathery texture.
Seasonality: Semi-evergreen tree for the most part but does shed leaves in March and April. Fresh leaves are translucent in a beautiful rosy colour. Figs ripen through the year at intervals—fruiting period varies between trees.
Family: Moraceae. Plants of this family contain a milky latex.
Origin and distribution: Native to India and found throughout the country in its cities, villages and forests.
‘The Banyan Tree’ from The Crescent Moon by Rabindranath Tagore
O you shaggy-headed banyan tree standing on the bank of the pond,
have you forgotten the little child, like the birds that have nested in your branches and left you?
Do you not remember how he sat at the window and wondered at the tangle of your roots and plunged underground?
The women would come to fill their jars in the pond, and your huge black shadow would wriggle on the water like sleep struggling to wake up.
Sunlight danced on the ripples like restless tiny shuttles weaving golden tapestry.
Two ducks swam by the weedy margin above their shadows, and the child would sit still and think.
He longed to be the wind and blow through your resting branches,
to be your shadow and lengthen with the day on the water,
to be a bird and perch on your topmost twig,
and to float like those ducks among the weeds and shadows.
FIVE
TALKING
TO TREES
Unlike animals, trees and plants don’t move around. We often think that they are not as interesting to observe as animals. Certainly, we may never think of talking to a tree, or even consider that trees can talk to one another.
But in 1983, David Rhoades and Gordon Orians (scientists at the University of Washington) while studying the Sitka willow, observed something that turned our ideas of plant communication upside down. When the leaves of one tree were attacked by caterpillars, the tree responded by making the leaves more unpalatable, filling them with poisonous chemicals. This made sense. Surprisingly, neighbouring trees more than 3 metres away, which were not attacked, also reacted in the same way. This observation was astonishing. It suggested that neighbouring trees received warning signals of some kind from the tree under attack. Other scientists working on other tree species, such as the poplar and the sugar maple, also found evidence of similar signalling.
At first, there was a lot of positive ‘buzz’ around the idea that trees could communicate. But later, many influential scientists criticized these studies as being anthropomorphic—falsely attributing ideas of human emotion to trees. The criticism was so severe that the main discoverer, Rhoades, had to quit the field of science altogether. The idea of talking trees was dismissed for several years.
Several years later, a number of research studies conclusively showed that Rhoades was correct. Wounded trees could indeed communicate with each other. They did this through signals sent through the air. When the leaves of one tree (or plant) were attacked and eaten, it released a cloud of chemicals into the air. Other trees nearby sensed these chemicals and were alerted to danger. One of the most dramatic pieces of evidence came from Transvaal, South Africa, where an African scientist, Wouter Van Hoven, was studying the unexplained mass death of kudu, the African antelopes. The kudu grazed heavily on acacia trees during a prolonged drought and the trees were in danger of dying. The trees that were overgrazed began to emit puffs of ethylene, warning other trees located at an average distance of 45 metres! All the acacia trees in the area ramped up the tannin production in their leaves, which was harmful for the kudus. The group response by the acacia trees led to the mass death of over 300 antelopes, poisoned by the increased tannins in the leaves.
Is this kind of communication intentional or accidental? Some scientists suggest that trees may be producing volatile chemicals like ethylene to quickly signal to their own leaves. The fact that their neighbours also pick up the signals may be unintentional. Tree neighbours may in fact be eavesdropping on private communications. But chemical signalling does not take place only in the air. Trees also communicate via their roots, sending chemicals out into the soil. Here, the evidence seems clearer that trees are intentionally talking to other trees.
In 1997, while studying the forests of British Columbia for her PhD thesis, Suzanne Simard made a discovery that revolutionized our understanding of tree communication. Trees of two different species—Douglas fir and paper birch—were in constant conversation, even though they were hundreds of metres away. These trees sent messages to each other via an underground network of fungal threads, or mycelia, which connected roots of different trees. During the summer, paper birch trees produced more food than the fir trees, which were in the shade of these larger trees. During the hot months, the birch trees sent food to the fir trees via the mycelial network. In the winter, the birch trees lost their leaves and could no longer photosynthesize food. Fir trees, which retained their needle-like leaves, not only generated food, but also passed on some of it back to the birch trees. Meanwhile, in a ‘you scratch my back, I’ll scratch yours’
network of mutual benefit, the fungus networks also benefited—they were sustained by the food sources that they passed on from one tree to another.
Using this network, which some scientists have dubbed the Wood Wide Web, trees were able to support each other during times of plenty and periods of stress. If one tree was being attacked by a pest, it sent signals to other trees to increase production of ‘natural pesticides’ to repel attacks. When a tree was damaged, leaving it less capable of making its own food, other trees sent it food through this underground network.
Trees know if their neighbours are kin, that is genetically related family members. They tend to offer greater support to related individuals, creating familial support networks of mothers, daughters and granddaughters. But trees also cooperate outside the family. Trees of different species talk to each other and take care of each other, as the research of Simard and her colleagues has shown.
Especially relevant for us in cities, research on forests shows that ‘mother’ trees—the oldest trees in a region—are essential for the survival of the entire community. These trees are connected to all other trees. When they are cut down, other trees send food to them via the underground fungal network, keeping them alive for decades after they have been cut. In forests in Germany, tree stumps cut over 500 years back have been observed to be alive, even though they lack branches and leaves, all because their neighbours are sustaining them.
Plants and trees don’t just emit chemicals into the air and soil. They also do something more obvious to humans—they produce sounds. We hear the rustling of leaves and the creaking of branches. It is soothing to stand under the shade of a large peepul tree in a busy city area and listen to the constant rustling sound of its leaves. But trees and plants also produce a number of sounds that are inaudible to our ears, at wavelengths that are too low or too high for us to pick up. Now scientists are beginning to suggest that trees may be communicating with other plants, and even animals and insects, via sounds that we may have missed simply because we never thought of it.
Ancient human societies have long believed that people can talk to trees. In ancient Persian, Chinese and Indian mythologies, there are frequent references to the Wakwak or Vagh Vagh tree, which bears fruits that look like human heads. When the fruits ripen, the trees begin to talk, say a number of beloved old fairy tales. Mythologies from Greek to English talk of oracle trees—trees that can predict the future. Alexander the Great was believed to have received a warning from a Wakwak tree of the end of his life and the destruction of his empire. More prosaically, forest tribes may also be using trees to communicate with each other. The Waorani tribe, in the forests of the Amazon, uses the buttress roots of giant ceibo trees to communicate across great distances. The roots produce a booming sound when thumped, much like a subwoofer in a sound system. This low-frequency sound travels across long distances in the forest, helping people find each other when separated. Many other forest communities have independently discovered the usefulness of buttresses. The Jarawa, an indigenous community that lives deep inside the forests of the Andaman Islands, also use buttress roots (of other species, for example species of Terminalia and the false hemp tree) to communicate when they are out of sight, and to warn others of danger.
Much has been made of humans communing with trees in cities as well. Several city gardeners talk to their trees and plants, firmly believing that this helps them grow. People even play music to their plants depending on their own preferences. Anecdotes seem to suggest that plants prefer classical, soothing music—whether Western, Indian or Chinese. Music with harsh sounds or strong beats, like rock music, seems to be counterproductive, making plants grow even more slowly. But research studies are still inconclusive. Nobody has been able to establish whether, or how, talking to trees helps in their growth, let alone tell us once and for all what kind of music they like.
But this does not deter a growing number of tree whisperers from cities across the world, who have launched initiatives to get people more connected with nature. Tree whisperers in cities like Bengaluru conduct open-air workshops at tree festivals, getting people to take off their shoes and socks, walk barefoot on the grass with their eyes closed, walk up to a tree and place their bare feet on the roots, later taking their feet up to the bark. With their eyes closed, how does the bare soil feel? And the grass? The bark? Psychologists say that hugging a tree reduces stress. Similarly, while we all love to admire trees, closing our eyes to focus on the sounds they make and feeling their bark and leaves with our hands, feet, arms and legs get us to commune with them in a completely different way.
Biologist David George Haskell has written extensively on his experience in talking to trees. His latest book, The Songs of Trees: Stories from Nature’s Great Connectors, describes a year he spent with twelve different trees around the world, from Israel to Ecuador to New York. He describes how different species make sounds that are very characteristic. A balsam fir hisses in the wind, while the stiff, needle-shaped bristles of a pine tree generate an intense noise. Attaching ultrasound sensors and microphones to trees, he shows us how trees become noisier on summer afternoons, as the sun’s overhead heat dries out their sap, breaking the long water columns inside the tree core, creating a number of little ‘clicks and fizzles’.
There are a number of puzzles that still remain about trees in cities though. For instance, when we plant trees in a row along a street, can they create new connections between their root systems? Do fungal networks develop below the soil, if concrete and tar surfaces are laid on top? We need new research to help us answer these questions.
As yet, no one has studied the science of tree communication in cities. What messages does this research on tree communication hold for trees in cities? In many Indian cities, large trees are cut because they are ‘over mature’, a term that many foresters use to justify chopping old trees. Planners speak of replacing these massive giants with young saplings. But if these trees are more than individuals and are in fact central nodes that support entire communities of trees, we are impacting the future survival of city trees in ways we have not thought of. We should focus on protecting the giant heritage trees left in our cities, as they help to sustain a network of trees near them. Finally, beyond the physical and ecological, how does this research help us develop a different imagination of trees? Is a city with trees, any sort of trees, desirable? Many people relate to trees as species, often based on their childhood memories of playing under one kind of tree and plucking fruits from or climbing another. One large tree may be as good as another if we do not know its name or identity. But people also have an affinity for specific species—some like the amaltas for its spectacular blossoms, while others have a belief that the neem tree is good because it purifies the air.
Going beyond this, can we relate to trees as individuals with whom we develop a special affinity? Many people do this for sacred trees. A peepul tree in a local temple, or a date palm in a favourite much-visited dargah takes us into a mood of contemplation of a higher power. In cities, we may have memories of a favourite mango tree in our grandmother’s backyard. A tree on whose branches we spent summer days with a pile of unripe mangoes, a bowl of salt and chilli powder, and a good book—only to be dosed with a spoon of castor oil at night. The famous American poetess Marianne Moore was deeply attached to a Camperdown elm tree in a park in Brooklyn, New York. In her eighties, she wrote a poem to the tree, ‘The Camperdown Elm’, which inspired a local group to protect this tree and other heritage trees in the park.
We have millions of trees in our cities. Can we develop a similar affinity for them? There are millions of us as well, of course. So perhaps we can, if we begin to recognize each tree as an individual, taking the time to talk to them—and listen to the wisdom they offer us in return. The group events that tree whisperers conduct help city dwellers get in touch with their inner green spirit through touching, tasting, smelling and feeling trees. These innovative approaches are much needed to help us understand what
trees are saying. If we learn how to communicate with trees in multiple ways, through science and through imagination, we can also learn how to protect our city trees from the threats of urban stress that are all around them.
SIX
PALMS:
SUPERSTARS
OR HAS-BEENS?
Indian cities are going through rapid changes in their preferences for trees. Moving away from trees such as mango, wild badam and silk cotton, many cities have begun to favour palms. Pretty as a picture, gracefully swaying palms add to the visual beauty of landscapes. From high-end apartment complexes to information technology (IT) campuses and city parks, exotic palms have become the new global superstars, assiduously courted and planted in cities as far apart as Chandigarh, Mumbai and Bengaluru. Where does our fascination for exotic palms come from?
The view of palms brings to mind images of sunny beaches. They symbolize luxury, leisure, and the idea of living life king-size on a coastal resort, with a drink in hand. Palms are also a symbol of southern California, where so many Indians participated in the IT boom of the 1990s. These palms were imported from Mexico and the Mediterranean, and popularized in the gardens of wealthy residents across California in the early 1900s. They were brought in for their decorative looks. They did not provide shade, much needed in the hot semi-arid desert landscape of southern California, nor did they provide edible fruit, or any other useful products. But the association with the tropics and the Mediterranean, and the very fact that these were exotic trees, reinforced the idea of southern California as a place of glamour and entertainment. In fact, the very attributes that made the palm purely ornamental—the lack of messy fruit, spreading roots and large branches—made it a favourite with city officials, who found it easy to plant and maintain this tree on major roads.
Cities and Canopies Page 4