Over the years, the city has lost nearly 100 species of native shrubs, trees and grasses due to various factors, including sewage contamination of waterbodies, increased demand for biological oxygen, and introduction of alien species

Trees are the best monuments that a man can erect to his own memory. They speak his praises without flattery, and they are blessings to children yet unborn – Lord Orrey

If one is to go by this phrase, Madras city once had the greatest native monuments.

Releasing of raw sewage into waterbodies, increased demand for biological oxygen, decrease in dissolved oxygen levels in waterbodies, and introduction of alien species have led to the disappearance of hundreds of species of plants, say forest authorities and researchers.

S. Subbarayalu, former principal chief conservator of forests, who authored a book on Dr. Hugh F.C. Cleghorn, the father of forest conservation in India, says that nearly 100 species of native shrubs, trees and grasses have disappeared.

Dr. Koening was the first British botanist to record the flora of Chennai in 1768. Whenever he had doubts about the species, he would send them to London, indicating the place where they had been collected from, says Dr. Subbarayalu.

More than one-and-a-half centuries later, P.V. Mayuranathan, an Indian botanist, recorded the flora, which became the basis for flora studies in the future. Whatever species Mayuranathan recorded in 1929 have slowly disappeared from the city’s landscape. This is evident from studies of later years.

A study of flora of Chennai in 1987 showed that nearly 100 species — recorded in the earlier study — that once occupied the city’s landscape had disappeared, says Dr. Subbarayalu.

Citing the example of a plant known as neer kizhangu in Tamil, Dr. Subbarayalu says, in the 1800s, this plant was found in the Spurtank area in Egmore. It was an edible plant, cooked and eaten by the working class people of those days. “One cannot find this plant anymore in Chennai,” he says.

Another one is neer paruthi, belonging to the shrub species. Its bark was used for decorative purposes, says Dr. Subbarayalu. This too is no longer found in Chennai.

R. Pauline Deborah, assistant professor, department of plant biology, Women’s Christian College, says a good number of tree species native to Chennai have disappeared over a period of 50 years.

Records show that in Pallavaram, there was once an area was called ‘Iluppai Thoppu’. “It is difficult to sight the iluppai tree in Chennai these days,” she says.

Another example is mangroves along the coastline of Chennai. Records show that mangrove patches were seen along the Buckingham canal behind the University of Madras campus, about 25 years ago.

“Even the small patch of mangroves found along the Adyar river (behind Theosophical Society campus) is under tremendous biotic pressure due to sewage mixing with the river water,” says Dr. Deborah.

Caper tree, small-headed Kadamba, Vanni, Trincomalee teak and Benjamin’s Fig, to cite a few, are some of the species that were part of the city’s landscape nearly 100 years ago.

Now these species are found only in a few places such as Theosophical Society, Guindy National Park, Nanmangalam and Vandalur reserve forests. Nearly 75 species of trees from Madras have disappeared, says Dr. Deborah.

In the past, in many temples, native tree species were protected in the name of sthala vruksham. Such a system helped in maintaining the ecological balance. It doesn’t exist anymore, resulting in the disappearance of several native trees from Chennai, say botanists and researchers.