The forest department of Delhi has launched a project to remove the invasive vilayati kikar (Neltuma Juliflora) from the central and southern Ridge areas to restore ecological balance. Labourers are digging pits to plant native species during the monsoon season. However, the process faces challenges and criticism from environmental activists who allege that heavy machinery like JCBs damages ground vegetation and biocrust, which are essential for soil health.
Invasive Species Dominance
For nearly a century, the Ridge has been dominated by vilayati kikar, an invasive species originally from South and Central America. This fast-growing tree forms dense thickets, blocks sunlight, and suppresses the growth of native vegetation.
Earlier Removal Efforts
The removal of kikar began in 2022 on a small patch in central Ridge using canopy lifting, where branches were pruned to allow sunlight to reach the ground. Native species were planted around the kikar to encourage growth. This exercise was extended to about 70 hectares, and species like bistendu, peepal, banyan, and arjun were geo-tagged. A forest official stated, “The geo-tagged saplings with data on their numbering, species name, and geo-coordinates will be uploaded on the portal of the forest department so that people can go and check themselves.”
Current Project Scope
Following the preparation of Delhi's first 10-year working plan by the Forest Research Institute in Dehradun, the forest department initiated removal of vilayati kikar from 120 hectares of central Ridge and 600 hectares of southern Ridge, planned over five years. A total of 14 lakh trees and 14.5 lakh shrubs will be planted this year. The working plan, effective until 2036-37, focuses on systematically removing three major invasive tree species: vilayati kikar, eucalyptus, and leucaena leucocephala (river tamarind or subabul), which together account for nearly 40% of the capital's forest growing stock. The plan states that only 20% of a given forest section will be treated each year to minimise ecological disruption.
Challenges and Methods
“In some cases, after a native species becomes strong, we completely remove vilayati kikar,” said a forest official. “We have engaged several labourers to dig holes for planting fresh saplings during the monsoon. As the Ridge has rocky patches, we sometimes use JCB machines to dig holes or remove the stump of kikar which has penetrated deep into the soil.” The official added that ground vegetation is proper in patches where vilayati kikar were removed a couple of years ago.
Environmental Activists' Concerns
Environmental activists have raised concerns, claiming that several native herbs and shrubs, including gangeti and kair, are being destroyed during the process. Chetan Agarwal, an independent forest analyst, said, “The population of vilayati kikar and subabul should be controlled in a phased manner, not by large-scale felling and uprooting with bulldozers that cause huge collateral damage to the undergrowth. During a recent visit to central Ridge, we saw JCB bulldozers being used to clear the ground of all vegetation and remove kikar stumps. The forks of the machines dig holes to uproot them, but in the process, the entire ground cover is being cleared. With decades of protection, the Ridge is rich in herb and shrub diversity with thousands of plants per hectare, which are now being virtually 100% removed in the process of clearing the vilayati kikar.”
Importance of Biocrusts
Pradip Krishen, author of the acclaimed book Trees of Delhi, highlighted the importance of biocrusts for soil formation and stabilisation. “Biocrusts begin to form when cyanobacteria colonise the soil surface. These pioneering microbes produce sticky substances that bind loose soil particles together, creating a stable, sponge-like layer capable of retaining moisture after rainfall. Over time, this moisture-rich and protected environment supports the growth of other organisms, such as mosses, lichens, green algae, and fungi, gradually developing into a complex biological crust.” He added that scientists have been studying them closely for the past 10 to 12 years.
