The great siris of India’s cities

These majestic trees burst into bloom in summer, support hundreds of birds and insects, and inspire a myriad stories

Published - June 20, 2024 03:15 pm IST

The siris captured in late evening light

The siris captured in late evening light | Photo Credit: Sunil Rajagopal

I live near a siris (Albizia lebbeck). It stands shoulder-to-shoulder with a copper pod, flanked by two smooth-skinned gulmohurs. The siris, however, is not gregarious even with its own kind. It bends away from them, draping its rounded, umbrella-shaped shade gently over our yard. Trees do not like their canopies to touch.

Every year, I know summer is coming from the sudden abundance of tiny, wandering red ants and colourful picturewings framed against the sky. They arrive in time for the siris blooming in a burst of fluffy white pom-poms, which slowly turn a pale yellow, emanating a mellow fragrance that lingers on at night. Ants, flies and stingless bees swarm; butterflies like the restless Green-tailed Jay and the slower, iridescent Great Egg Fly pause to settle on the flowers.

The picturewings hover over the trees in small groups on stained glass wings, filtering black and yellow light from the blue sky. They look aimless and slow but are actively hunting the flower feeders. In turn, the picturewings and bees are picked off mid-air by agile Blue-tailed Bee-eaters. Other birds also join the melee on the siris — flamebacks, white-throated kingfishers, drongos and tailorbirds all making use of this feast.

A Tailed Jay on a siris blossom

A Tailed Jay on a siris blossom | Photo Credit: Sunil Rajagopal

A Blue tailed Bee-eater hunting near the copper pod blossoms

A Blue tailed Bee-eater hunting near the copper pod blossoms | Photo Credit: Sunil Rajagopal

Who remembers the vaagai?

The siris is an Indian native and was once fairly widespread. Kalidasa personified Parvati with its delicate flowers in his Kumarasambhava. In Tamil, it is the vaagai, legendary in Sangam literature for its connotation to victory. Legends speak of Durga gathering her strength under a vaagai, before proceeding on her war with Mahisha. For this reason, garlands of its flowers were apparently worn by warriors.

Almost every part of the tree is considered useful as per Ayurvedic texts. Later, many trees with mimosa-like leaves came to be called vaagai or variations of it. In Kerala, the Madagascar-born gulmohar is often referred to as a vaaka.

How many of us can recognise or name a vaagai now? How many from Kerala would know the picturewings by their Malayali name, Onathumbi — literally the dragonfly of Onam. They would typically emerge during the harvest season, during August-September, to feast on the burgeoning insect population. Built over wetlands and paddies have made them uncommon in cities, so much so that most of us have forgotten their names. The siris, too, is not as conspicuous now, ignored in places as an avenue tree due to its deciduous and reclusive nature.

Under the siris canopy

Under the siris canopy | Photo Credit: Sunil Rajagopal

Tapping into collective memory

Naming something has an unseen power. Especially in nature, which many of us deem indistinguishably homogenous. Names, especially those in the local tongue, lead to stories, and stories tap into our collective memories. Learning the name of a tree or a bird or an insect often means learning something about it: its uses, its ties with local culture and geography, or its connections to other forms of life. Naming a living being is also an awareness of its position in a seasonal cycle or its place in time.

Above all, we understand something best when it can be quantified, especially in terms of its usefulness. Picturewings, for example, serve as biological pest control. As creatures of all three realms — earth, water and sky — dragonflies are excellent indicators of wetland health. Terrestrial insects are declining globally at 9% per decade. This is a critical number when you consider insects pollinate 75% of global crops and 80% of wild plants. As the base of most food chains, fewer insects mean less food going around and yields dropping everywhere. An ecosystem ‘service’ that a value in billions of dollars would not do justice to.

Common picturewings

Common picturewings | Photo Credit: Sunil Rajagopal

Saviour of urban heat islands

Trees like the siris also combat heat island effects (which occur when natural land cover is replaced with pavements, buildings, and other surfaces that absorb and retain heat) and lower temperatures locally by several degrees. Not just by its shade but by allowing cities to perspire through leaf transpiration. They decelerate raindrops, and their roots control surface run-off to allow better percolation. Dense foliage lowers particulate and noise pollution. All this while boosting insect and bird diversity. The extent of these effects varies with species, their structural features and geographic suitability.

It may be interesting to study the impact of Cyclone Michaung on Chennai last December, juxtaposed with the presence of tree cover. At a glance, it would appear that localities with more tree cover and consequentially some amount of exposed soil for drainage fared better with flooding. They are also more likely to be the places with usable ground water availability. Unfortunately, public parks and privately owned gardens take up a lion’s share of our urban green spaces. Making trees an indicator also of discrepancies in socio-economic well-being, sustainability and liveability of a city.

The author is a birder and writer based in Chennai.

The third article in a series that looks at urban spaces as havens for biodiversity and often overlooked species.

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