Native, not exotic: The trees Delhi needs...
The prominent native trees of Delhi — amaltas, palash, chamror, siris, barna, kusum, and kachnar — bear a mix of flowers
New Delhi The Delhi high court, on Wednesday, emphasised the need to plant more native trees in the city instead of bringing in exotic species, like the palm, and directed civic agencies to explore varieties suited for Delhi’s ecology. The high court’s directions were a reiteration of what experts and tree enthusiasts have been stressing for long — that the bright-yellow amaltas, the crescent flowered palash, or the bright-purple kachnar — Delhi’s own trees, are well-suited for the climate and ecology of the city, while non-natives like the palm or cherry blossom use up resources which damage the environment.
The prominent native trees of Delhi — amaltas, palash, chamror, siris, barna, kusum, and kachnar — bear a mix of flowers. Additionally, they are self-sustaining species that adapt to the city’s climatic conditions and do not need regular care after the initial years, said experts.
“These trees can be grown in large parts of Delhi, including the Yamuna floodplains and all of Lutyens’ Delhi. The most appropriate trees are pilkhan, siris, amaltas, and kusum, as they perfectly adapt to the conditions in Delhi. They don’t need watering or nutrient supplements, once established,” said Pradip Krishen, author of the seminal book Trees of Delhi.
Tree activist Padmavati Dwivedi echoed the sentiment, and said that while considering avenue trees, which are both ornamental and native to Delhi, then one must look at palash, amaltas, etc., adding that they not only look aesthetically pleasing but do not require large spaces. To be sure, avenue trees are ones planted along roads, streets, or avenues, typically selected for their shapes, especially height.
However, the Capital’s civic agencies took to the vanity project of planting non-native species as avenue trees during beautification projects or plantation drives. A prominent avenue tree seen along the NH8 up to Dhaula Kuan, covering parts of the Delhi Cantonment towards the Sardar Patel Marg is the palm or Phoenix sylvestris. Palm has also been planted in the run-up to the G20 summit on both Aurobindo Marg and Nelson Mandela Marg as part of the Public Works Department’s (PWD) streetscaping project. However, a majority of these palms, as pointed out by the court, are dying.
This apart, agencies are also attempting to grow both the chinar and cherry blossom in the city. While the former, from Jammu & Kashmir, is known for its amber, red, and yellow leaves, the latter is native to Japan but is increasingly being grown in places such as Bengaluru, Mumbai, Shimla, and Shillong.
“The British, too, made the mistake of choosing trees which they thought were evergreen, like the jamun or arjun. But these trees are evergreen only when they grow along perennial water courses,” Krishen said.
Vallari Sheel, a researcher and urban ecologist, said that exotic species require more maintenance and offer fewer ecological benefits to the environment around them, with some species also running the risk of becoming subsequently invasive.
“Native species are adapted to the local environment and have evolved with the local fauna to provide them both food and shelter. On the other hand, “ Exotic species not only require more water or maintenance can often become invasive,” said Sheel.
However, not all non-native species are bad for the environment, if one considers specific features while choosing particular varieties. For instance, two non-native trees that have adapted well to the ecology of Delhi are the anjan and the khirni. “They will not be suited as avenue trees, as they require a lot of space, particularly anjan. However, they do well in spaces like parks,” said Dwivedi.
Faiyaz Khudsar, scientist at the Yamuna Biodiversity Park (YBP) and scientist-in-charge of the Biodiversity Parks Programme of the Delhi Development Authority, said that one needs to largely look at broad-leaved species for a city such as Delhi, which not only trap dust but also reduce the heat-island effect and provide habitat and food to birds.
“The native trees are well suited for this purpose. The kachnar, for instance, has four different varieties — ranging from Bauhinia variegata, which is the tallest, to smaller ones like Bauhinia racemosa — all of which can be seen in Delhi,” said Khudsar.