Amid concerns over the low survival of transplanted trees, the Delhi government has commissioned a scientific study to understand survival trends and planned to import advanced tree transplanter machines from abroad to make the process more effective.
Officials said the Forest Research Institute, Dehradun has been asked to conduct a study within three months. “These steps are being taken to make changes in the Delhi Tree Transplantation Policy 2020 based on scientific evidence,” they said.
The move follows concerns over low survival rates of transplanted trees, with a previous report by the Forest Research Institute estimating an overall survival rate of 35.45 per cent, with significant variation across species.
Forest department data also showed that of the 1,357 trees transplanted between 2019 and 2022, 578 survived, translating to a survival rate of 42.5 per cent.
Delhi Environment and Forest Minister Manjinder Singh Sirsa told PTI, “We are taking steps to make the tree transplantation process in Delhi more effective and better. We are conducting this study to understand why transplantation has faced persistent challenges over the years.
“The findings will help us adopt a more scientific approach based on field evidence and expert inputs, and make the city greener,” he said.
The minister further said that a new Expression of Interest has been floated that will also help in bringing advanced tree transplanter machines from aborad to the national capital that can improve survival rates and help the process.
A senior official aware of the matter said the institute had sought a year to complete the study but that they have been asked it to submit the report within three months “so that necessary changes can be made and further loss of transplanted trees can be prevented”.
Speaking about the new machinery, officials said that existing methods use backhoe loaders that often damage roots and cause transplant shock.
“These machines have been used in Gujarat and can uproot medium-sized trees. The proposed study will help assess their effectiveness in Delhi conditions,” officials said.
The Forest Research Institute report noted that survival rates remain below expectations and vary widely, prompting a review of existing practices which officials said need greater standardisation and scientific inputs.
According to a minutes of a meeting of the Delhi forest department with empanelled agencies held in January noted that agencies were not consistently following permissions issued by Tree Officers or adhering to approved Tree Preservation Plans and timelines.
The meeting also stressed the need for stronger oversight, including inspection of transplantation sites by Tree Officers and directions to improve survival outcomes.
Officials further suggested developing a system to capture detailed data on each transplanted tree, including species, girth and survival rates, to guide future policy decisions.
Consultations with the empanelled agencies highlighted that factors such as species, age, girth and size play a critical role in determining survival, reinforcing the need for a more scientific and standardised transplantation process.
The meeting identified species-specific trends. Trees such as peepal, bargad, gular, pilkhan, arjun, semal, amaltas, sahajan, gulmohar, peltophorum and alstonia showed relatively higher survival and can be transplanted up to a girth of 350 cm.
Ficus species were found to have the best survival performance among transplanted trees, and officials noted that their branches could also be used for plantation through vegetative propagation where feasible.
In contrast, species such as mango, jamun, tamarind, neem and jackfruit showed lower survival rates, especially at larger sizes, and may not be suitable for transplantation beyond 50 cm girth.
It was also noted that species including papdi, sheesham, lasoda, desi kikar, khejri, ronjh, bakain and ashoka with girth above 200 cm show poor survival and may generally be avoided.
The meeting stressed that post-transplantation maintenance is a key factor and suggested that agencies be made responsible for upkeep for at least two to three years to improve survival outcomes.
It also suggested reviewing the requirement of transplanting 80 per cent of affected trees, noting that the target may be difficult to achieve in all cases due to on-ground constraints.
Under the Tree Transplantation Policy, 2020, transplantation is mandatory in development projects where tree felling cannot be avoided. The process begins with a site survey and preparation of a Tree Preservation Plan, followed by pruning, root ball preparation, relocation and replanting.
The transplantation process typically takes three to four months, followed by a maintenance phase of at least one year. Payments to agencies are linked to survival rates, with penalties if survival falls below 50 per cent.
The policy mandates that at least 80 per cent of affected trees must be transplanted, while three species, leucaena leucocephala, eucalyptus globulus and prosopis juliflora, are excluded from transplantation.
