The Forest department in Delhi plans to remove invasive alien subabul and eucalyptus trees from the city and replace those with species suitable to the national capital's ecology, officials have said.
Subabul trees, native to central and south America, and eucalyptus trees, which are native to Australia, have the potential to outcompete indigenous vegetation and alter ecosystems.
The Forest department in Delhi plans to remove invasive alien subabul and eucalyptus trees from the city and replace those with species suitable to the national capital's ecology, officials have said.
Last April, the government launched a pilot project to replace invasive Mexican trees 'vilayati kikar' with indigenous species in the central and southern ridge. Spread over 7,500 hectares in Delhi, 'vilayati kikar' is not conducive to the city's environment, the officials said. However, there is no official estimate of the extent of the spread of subabul and eucalyptus in the national capital.
Subabul trees, native to central and south America, and eucalyptus trees, which are native to Australia, have the potential to outcompete indigenous vegetation and alter ecosystems. They have a high water demand and can deplete groundwater resources if grown in areas with limited water availability.
A discussion on the plan started after the Delhi Urban Art Commission (DUAC) wrote to Environment Minister Gopal Rai last September, requesting him to "explore the possibility to exterminate the invasive foreign species at the earliest". The spread of these trees is preventing desirable native species from thriving, according to the DUAC.
The process of removing the alien tree species, even if treated on a critically urgent basis, may take decades due to the profligate dispersal of their seeds that will continue to germinate for years, it said.Forest department officials said Delhi's green cover has increased from 20 per cent in 2013 to 23.06 per cent (342 square km) in 2021. They are now focusing on improving its quality in the next phase.
"We have been following biological supression method for vilayati kikar. The same method will be followed for subabul," an official said. In the biological suppression method, a mature tree is heavily pruned and fast-growing trees, browsing shrubs and creepers are added in its place.
The official said mass uprooting and cutting of the invasive trees might result in abrupt reduction of Delhi's green cover and loosening of the soil around them that could, in turn, increase dust pollution in the city. The DUAC, however, said cutting these invasive trees slowly is unlikely to yield material benefits as the remaining trees would continue to disperse seeds in the area.