Delhi’s foliage has many foes

Over the last decade the capital has lost tens of thousands of trees

Updated - December 04, 2021 10:40 pm IST

 Amaltas tree (Cassia fistula) and Gulmohar trees in full bloom at Shantipath in New Delhi

Amaltas tree (Cassia fistula) and Gulmohar trees in full bloom at Shantipath in New Delhi

When the British shifted colonial India’s capital from Calcutta to Delhi, they decided to populate the city with trees. There was a deliberate method to the greening: trees with large canopies were chosen to match the architectural grandeur; jamun ( Syzygium cumini) and Arjuna ( Terminalia arjuna) had the added advantage of being evergreen, ensuring the streets remained foliaged all year; in spring, the amaltas ( Cassia fistula) drenched the city in yellow — but they were deliberately not planted around the corridors of power because they shed their leaves in early summer and their bare branches would have, in the English imagination, been distinctly unsightly.

Over the next century, Delhi would become one of India’s greenest cities with 7% of its geographical area under tree cover. Its trees have been astutely chronicled and some given a heritage tag by the Delhi government — including the salvadora ( Salvadora oleoides ) near the Qutub Mosque, the banyan ( Ficus benghalensis) at Bhikajikama Place, the mango tree ( Mangifera indica ) at Lodhi Garden, the Arjuna and Ashokas ( Saraca asoca) at Raj Ghat Memorial and the pilkhan ( Ficus virens ) at Deer Park in Hauz Khas.

But over the last decade Delhi has also lost tens of thousands of trees. Between 2014 and 2017, 15,000 were felled for various development projects. Then, to execute three phases of the Delhi Metro, nearly 46,000 trees were cut between 2004 and 2018, according to a petition in the Delhi High Court.

21st century Chipko

Last week, the news that over 14,000 trees were marked for felling in South Delhi by the National Building Construction Corporation (NBCC), sparked an unprecedented public outcry.

 

In Netaji Nagar alone, 3,906 trees were marked for felling, representing 73 species — including Ashoka, jamun, gular ( Ficus racemosa) , sahjan ( Moringa oleifera ), champa ( Magnolia champaca ), gulmohar ( Delonix regia ) and amaltas — species that encapsulate the city’s ecological heritage.

The outrage at the NBCC project grew quickly on social media, and on the ground translated into a recreated ‘Chipko movement’. Residents hugged trees, held placards that said, ‘When we save trees we save ourselves’. The Delhi High Court last week echoed the sentiment when it asked if Delhi can afford to cut down so many trees for a housing complex.

The High Court stayed the tree-felling proposal, ordering that it be held off until July 4. Indeed much of the opposition arises from awareness and concerns about Delhi’s deteriorating urban environment.

 

In a city whose air quality is among the worst in the world, with pollution levels frequently breaching the ‘severe’ category, losing trees would defy logic: leaves are known to trap particulate matter — especially the smaller particulate matter of 2.5 implicated in respiratory problems. The U.S-based Nature Conservancy, for instance, estimates that large healthy trees reduce particulate matter levels by 7% to 24% around them. Trees also act as ‘umbrellas’ against dust, often a regular feature during Delhi’s summers. (But there are, conversely, some studies that argue that closely spaced trees and those with thick foliage can also block airflow in some regions, particularly if traffic is extremely high.)

According to the India State of Forest Report 2017, while Delhi’s total forest cover and tree cover have gone up by 0.25% and 0.13% respectively, ‘very dense’ forest cover in the city declined from 6.94 sq. km in 2015 to 6.72 sq. km in 2017; and ‘medium dense’ forest cover dropped from 57.1 sq. km to 56.2 sq. km. Parallelly, the diversity of bird species in the Garhimandu city forest in north Delhi has decreased — from 120 in 2014 to just 44 species this year, according to a survey by ecologist T.K. Roy.

Empty promises

Citizens don’t trust the government will follow up on its promises to plant new trees as compensation. In January 2017, the National Green Tribunal asked the Central Pollution Control Board to conduct surprise inspections at the NBCC construction site and report on the progress made in replanting. The team found deficiencies and violations of several environmental safeguards and the tribunal fined NBCC ₹10 lakh. While the tribunal permitted tree felling last year, it ordered that tree planting, or transplantation, must be done ‘as a precedent’ to cutting trees. But the replanting, by all accounts, has been scant.

And where trees are planted, ecologists say they are rarely trees native to Delhi — and often they are ornamental palms. Sometimes very water-intensive trees are chosen, impacting groundwater resources.

Delhi’s trees, however, have an enemy older than the bulldozer: a shrub, the ‘vilayati’ kikar. Prosopis juliflora, native to South America and the Carribean, took root here in the 1930s. It was brought into Delhi by the British and soon became an invasive species encroaching upon local flora, starving them of groundwater and nutrients. In Delhi’s ridge, or the forested ‘lungs’ of the city, the kikar has overwhelmed the acacia, kadamb ( Neolamarckia cadamba ) and amaltas. Its thorny leaves impede the movement of animals and its seeds can be poisonous.

For years, Delhi’s governments have tried a variety of methods to tame the kikar. It allocated ₹50 lakh in its budget in 2017, and approached the Forest Research Institute in Dehradun for solutions. More recently, a group of scientists have begun experimenting with a form of biological warfare against the kikar. They are looking to recruit a multitude of other species — bougainvillea, rubber vine, the Asian bushbeech — to choke the kikar of sunlight.

Delhi’s famous foliage clearly has a fight ahead — whether against concrete or kikar.

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