Tree transplantation and environmental conservation

Tree transplantation has gained traction in India to preserve green cover, in the face of urbanisation and infrastructure projects. But while it offers a compromise between development and conservation, the practice is complex, costly, and its long-term success remains a subject of debate among experts, as per a report by Mongabay-India (MI).

According to a Forest Research Institute (FRI) Dehradun study, urbanization and road widening projects in many parts of the country lead to removal of large number of trees every year. To reverse this trend the concept of transplanting of such trees from their original sites to the other available sites is gaining momentum, however no systematic studies on the subject is available to recommend. The tree transplantation process involves great engineering and arborist skills to make it work effectively apart from substantial amount of resources, money and time. Tree transplantation is a process of unearthing the trees and replanting them from their parent locations to new locations with objective of re-growing the trees at new locations. The key concern remains in protecting the root ball while pruning the wider roots.

The FRI study says that though hundreds of species are used in the urban environment, hardy native species are preferred over exotic species. The native species are found to survive better than exotic ones. The tree species which produce coppice shoots have better chances of survival after translocation if proper care is taken. The trees with poor health and structural defects are not favourable for translocation. One of the biggest-ever tree transplantation exercise in the country, over 5700 fully grown trees were transplanted to build Dwarka Expressway in the state of Haryana.

As the MI study explains, tree translocation or uprooting a mature tree and relocating it to another site where it can continue to grow is often employed as a mitigation measure in development projects to minimise the environmental impact of tree removal. Transplantation can also be an option for reviving uprooted trees after natural calamities.

The MI report quotes a study published in Nature Fund which stated, “Trees in forests (including plantations), if well-stocked, typically sequester carbon at a maximum rate between about age 10 and age 20-30 years. As an indication, at age 30 years, about 200 to 520 tonnes of CO2-e (carbon dioxide equivalent, a metric that expresses the impact of different greenhouse gases) are sequestered per hectare in forests with productivity ranging from low to high.”

The MI report adds that many Indian states have policies to encourage scientific tree transplantation where trees need to be cut. Delhi’s Tree Transplantation Policy, 2020 requires the scientific transplantation of at least 80% of trees in proposed project areas that cannot be preserved on site. Telangana government formed a tree protection committee in 2022, a nodal agency that encourages transplantation. Karnataka and Goa too have laws against tree felling. A tree act is under consideration in Tamil Nadu which would make felling trees a punishable offence.

However, the MI report warns that many environmentalists advise that in many cases, tree transplantation may not work, especially if not done scientifically. Root damage, improper creation of root balls and undesirable growing sites are some of the reasons for transplant shock and make trees more susceptible to diseases. In June this year, media reports noted that as per the forest department, 42.5% of the trees transplanted in and around Delhi, between 2019 and 2022, had survived. The success of transplanting depends on the health, species, age, shape of canopy, climate and time of day of transplant too. Care, maintenance and continuous monitoring are also most crucial both before and after the process. Species selection is of prime importance. Post care, which takes at least 30% of the total budget allotment, in transplantation processes is often ignored. A tree may be considered a transplant for at least two years and for as long as 10 years, depending on species and speed of recovery, no matter how old it is when planted. Continuous monitoring is important as it could get infected with pests and physiological imbalances might occur. Leaf scorch and premature fall coloration and early leaf drop are a few noticeable imbalances in transplanted trees.