A million trees a year can meet targets,not Delhi need: Experts

Worse,they could lead to long term problems like the creation of monocultures and the depletion of groundwater. But,this is a charge officials deny.

According to Ajay Mahajan of the NGO ‘Kalpavriksha’,the city’s civic agencies which are in charge of planting trees along roads and in parks,focus only on three or four types of trees.

“For roads,the current favourite is a tree called ficus benjamina. You’ll see it on avenues and central verges. Lakhs of these were planted during the Commonwealth Games. In some areas they’ve also planted a lot of frangipani. And for parks they choose polyalthia longifolia,which looks like the Ashok tree but actually is a different variety. Certain types of palm like the fishtail palm are also planted.”

Mahajan says of all four varieties are basically ornamental trees and none are native to Delhi.

“This kind of plantation is only to meet official targets. These trees are planted very close to each other and grow like hedges. So,they don’t provide shade or help in climate moderation. The temperature difference on the roads that have tall trees— like in Central Delhi — and those that don’t can be up to four of five degrees,he said.

It’s a pattern that’s evident in several parts of the city.

According to Pradip Kishen,author of the book ‘Trees of Delhi’,civic agencies and urban planners prioritise the planting of evergreen trees without realising that they are not suitable for the city.

“Planting too many evergreen trees is a bad idea because the natural pattern for trees in Delhi is to be deciduous since we don’t get rain for most of the year. If you go to any forest area in this part of the country you’ll find that only two per cent of the trees there are evergreen. You may only find them around river banks because they constantly need water,” Kishan says.

The problem is that these trees use up a lot of groundwater and that’s something the city can scarcely afford.

There are alternatives to the way things can be done in Delhi,and Kishen points out that there is a wealth of native tree species to choose from,which would serve very well as avenue trees.

“The Kosam tree which has been planted near IIT does very well in Delhi. There’s also the Bija and Rohini which are from the forests of Central India that would do well. The Anjan which is planted on Pandara road and Dalhousie road does very well since it grows in very dry forests and Mahua which is planted in Southend Lane is also a good tree for avenues,” he added.

SD Singh,CEO of the Delhi Gardens and Parks Society one of the key bodies in charge of tree planting,denied that there was any danger of creating monocultures.

“Apart from ficus benjamina and champa,we have also been concentrating on planting species like jamun,arjun,pilkhan,neem and baheda. Some of these trees may not exactly be native to Delhi but they belong to the Indian sub-continent and are suitable for Delhi’s climate conditions,” Singh said.