This may be counter-intuitive, but when a lot has to be done in a short time, a spot of “creative pausing” to take in the overall picture would be absolutely necessary. Because, hurrying into something purely on the basis of motivational rhetoric can pose the additional problem of having to undo the effects of an erroneous approach, which would further shrink the paltry time.
This thinking should be applied to tree-planting drives, most of which are usually solely numbers-focussed and rhetoric-driven. A greening initiative would be laudable if a focus on numbers is combined with the wisdom of marrying trees to their rightful space.
In this context, it is worth revisiting a tree-planting study that was conducted two years ago, and whose final recommendations were submitted to the Greater Chennai Corporation (GCC) in the first quarter of 2019. There is a scientific back-story to this exercise, which also had the right motivation points to drive residents’ welfare associations to action.
Here is its grand theme — two lakh trees to be planted every year, for five years with the net result that Chennai would have one million additional trees from that sustained exercise. The study came up with lists of tree species to address various topographical and geographical features. There were lists for coastal sections, arterial and sub-arterial roads, waterbodies and wetlands, parks and institutions and so on.
S. Balaji, retired Principal Chief Conservator of Forests at Government of Tamil Nadu, and now advisor to Care Earth Trust, who led this study, presents the background to it.
“The study was instituted by the Tamil Nadu Urban Infrastructure Financial Services Limited (TNUIFSL) on behalf of GCC. The detailed report was prepared by the Care Earth Trust with the support of INMASS and Chennai River Restoration Trust (CRRT), and submitted in March 2019.”
Balaji says that when the study had cystalised into a noticeable form, and collected all the necessary data points about all parts of Chennai and their specific greening requirements, a public consultation was organised (in February 2018), inviting residents’ welfare associations from across the 15 zones. The response is said to have been heartening.
“Besides the tree-planting exercises by the Corporation, there is a need for involvement of residents’ associations in greening activities,” says Balaji, suggesting that “One million trees in five years” is essentially a people’s target.
Altogether, 91 native tree species were identified as suitable for various parts of Chennai with their unique soil and topographical conditions.
With Chennai being largely defined by its coastal component, great thought has to be given to what trees thrive best in the coastal environment. In that context, thespesia populnea and terminalia catappa are among the trees that make the cut on account of their high level of salt-tolerance.
The recommendations for coastal areas, as also for the others, including waterbodies and wetlands in interior regions, the choice of native trees from a shortlisted group was also dictated by practical considerations such as space and the aesthetics of the area in question.
The study also looked at the existing greenery, defined by both native and exotic species.
On the question of exotic trees lining avenues, “We can’t entirely wish away these exotic trees.”
Pointing out that a good number of existing trees in Chennai are exotic — one of them is the ubiquitous raintree — he adds that while the goal should be promoting native trees, the city’s green exercises should also factor in making the best use of what already exists.
He drives home the point by referring to a situation along the Marina. “The few native thespesia populena trees found at the beach have, as expected, withstood the sustained spray of salt-laden air. And then you have a row of kigelia pinnata trees — an exotic species — which have also done well in these conditions. They are around for over 30 years, and they provide a lot of shade, at a section of the Marina where it is much needed,” says Balaji.
A stand of kigelia pinnata trees with their widely-spread branches are found near the main and much-visited section of the Marina.
Harini Nagendra, professor of sustainability at Azim Premji University, who has authored “Cities and Canopies: Trees in Indian Cities” along with Seema Mundoli, is on the same page about achieving city-greening goals by integrating existing exotic trees into the strategy.
“In Bengaluru, raintrees and copperpods are found in significant numbers, and they give a lot of shade, and the local butterflies and insects have adapted to these trees. They promote bio-diversity considerably,” says Harini.
On the question of putting tree species with high salt tolerance to best use, Harini states that they would be best utilised if they were planted in estuarine environments such as the one provided by the Adyar estuary.
Balaji says residents’ groups can get the lists of tree species, from the Greater Chennai Corporation.
A thespesia populnea bloom. Photo: Prince Frederick
Here are some of the trees from the lists
1. Arterial roads
Albizia lebbek (vaagai); Adenanthera pavonia (kundumani); Hadwickia binata; Lagerstroemia Regina's (poomarudu); Swietenia macrophylla; Terminalia bellerica
2. Sub arterial roads
Cassia fistula (kondrai); Bauhinia racemosa (mandarai); Calophyllum inophyllum (Punnai); Mimusops elengi (magizham); Madhuca longi folia (iluppai); Pongamia pinnata (pungan)
3. Coastal areas
Hibiscus tiliaceus (Malaii poovarasu); Terminalia catappa (naatu madam); Borassus flabellifer (panai); Thespesia populnea (poovarasu); Calophyllum inophyllum (Punnai); Salvadora persica (uvari); Manilkara hexandra (kanuppalai)
4. Along Waterbodies
Syzygium cuminii (naval); Neolamarkia cadamba (kadamba); Mitragyna parviflora (Siru kadambu); Mangifera indica; Borassus flabellifer (panai); Terminalia arjuna (neer marudu )
