The much-anticipated Bengaluru-Chennai expressway is being designed to significantly reduce travel time between the two cities. However, it comes with a substantial environmental cost. Reports indicate the project will result in the loss of over 9,500 trees, many of which have already been cut down. “Hundreds of trees on both sides of the highway have been chopped down. The highway, which was once known for its shade, lies barren. These trees could have been transplanted,” said B. Ilango, Founder of Jayam Trees Translocation, a firm that transplants trees across South India.

Tree transplantation or translocation is the process of uprooting and relocating a fully grown, mature tree from its original location to a new one. “It can be a crucial effort to conserve valuable mature trees, particularly in urban scenarios, if done in a scientific, sensitive and caring manner,” said Shobha Menon, Founder Trustee of Nizhal, an NGO that works towards connecting local communities for tree conservation in urban areas.

The method has gained traction in India as a way 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.

What is tree transplantation? Why is it done?

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. A study published in Nature Fund 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.”

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.

“While processing the request of various user agencies for diversion of forests (using forest area for non-forestry purpose), the forest department in Telangana is now insisting them to take up translocation of trees along with compensatory afforestation,” said Mohan Chandra Pargaien, Principal Chief Conservator of Forests & Chief Wildlife Warden, Telangana. A planted seedling may take at least three to 10 years to provide various intangible benefits including carbon sequestration and environmental amelioration while this can be achieved in a shorter period by switching from tree felling to translocation, Pargaien added.

Transplantation can also be an option for reviving uprooted trees after natural calamities. On July 23, 2017, a team of eight volunteers from Vata Foundation visited Government Girls High School in Telangana’s Nagarkurnool district to revive a fallen jungli jalebi tree, which had been uprooted during a summer thunderstorm but still showed signs of life. “I requested the school’s principal, Ms. Yashodha, to allow the students to witness the transplantation procedure. We could put the tree back in its original position in five hours as about 300 students and staff watched,” Uday Krishna Peddireddi, founding trustee of Vata Foundation said. The tree, which provides shade and fruits for the students, survived. To celebrate its resurrection, students tie a rakhi around it every year on July 23.

What are the drawbacks of transplantation?

Environmentalists advise that in many cases, tree transplantation may not work, especially if not done scientifically.

In one case, defying the norms of Tree Transplantation Policy, hundreds of mature trees in Delhi were transplanted kilometres away in an unscientific manner. “Trees from Central Delhi were transplanted to a contaminated site, which is more than 20 km away. It is a disturbance to the local biodiversity,” said urban ecologist Vallari Sheel. “Transplantation is a huge shock to trees. It is akin to cutting the limbs for a human.”

Root damage, improper creation of root balls and undesirable growing sites are some of the reasons that trees suffer from transplant shock, according to a paper by University of Kentucky, College of Agriculture, which adds that the trees stressed from transplant shock are more susceptible to diseases such as thyronectria canker, a fungal disease that affects the branches of the tree.

“Benefits such as microclimate regulation, shade, temperature reduction, habitat for wildlife such as birds are lost from the place the tree is removed from and it is not a simple case of these being just transferred from one place to another if a tree is transplanted,” Sheel said.

“When these trees are transplanted very far away from their original space, how does it mitigate the environmental gaps caused by removal from that neighbourhood?” Menon of Nizhal questioned.  “Removing even one tree can be harmful, in terms of loss of habitat for other living species. It increases pollution, causes temperature deregulation and soil erosion in that neighbourhood,” she added. Studies have validated that removing a tree, even if it is to be transplanted, accelerates soil erosion in that area as trees help stabilise and hold soil in place. Additionally, studies note that trees “remove air pollution by the interception of particulate matter on plant surfaces and the absorption of gaseous pollutants through the leaf stomata.”

Trees support entire ecosystems around them, even in urban areas, which could include soil mycorrhizae. It takes decades to build these ecosystems and only a few hours to destroy them, Sheel added.

In other words, transplantation should be considered only if the trees cannot be integrated in the design.

Even then, not all trees can be transplanted and not at all seasons are perfect for transplantation. “A tree over 20 to 30 years has a slower capacity to produce new roots, slower cell division and hormonal imbalance. A tree with diameter greater than 1.2 metres may not be a successful transplant. Hardwood trees are slow growing and transplanting trees such as tamarind, neem and vilvam are time consuming and requires high maintenance after transplanting,” added Menon.

Read more: [Explainer] Can planting trees mitigate climate change?

What makes a successful transplantation?

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. “From pruning to cutting to preparing root balls, transplanting difficult species (such as neem, mango and jackfruit) takes at least six months. For moderately difficult species such as tamarind, it takes three months, while easy ones such as gulmohar and peepul can be transplanted on the same day without any pre-treatment,” Ramachandra Appari of Green Morning Horticulture Pvt Ltd, who has been transplanting trees since 2010, said.

Species selection is of prime importance. “Ficus may do well, but the neem is not at all suitable. Almost all those species which regenerate easily by vegetative propagation, are promising and surviving well. Those species with high dependence on tap roots will not be suitable but those with fibrous/lateral roots tend to do well,” mentioned a study on transplantation.

Experts say that in many transplantation procedures, post care, which takes at least 30% of the total budget allotment, is 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, notes an article on post transplant care.

“Transplanted trees should be maintained for a year, ensuring there is no water stagnation, which can lead to their death. Trees should not be excessively watered; the amount of water should be carefully calculated based on rainfall and soil type,” said B. Ilango.

In India, tree transplantation is often done simultaneously with road-laying projects, which typically take place during the dry summer months. However, Peddireddi emphasised, “Trees should be transplanted only during the first monsoon rains until the end of winter. The technique for a successful transplant lies in ensuring good moisture content but not stagnation of water.” A transplantation guide by the Gujarat government mentions the preferred time for transplantation as monsoon and winter and that hot months between April and June should be avoided.

Continuous monitoring of a transplanted tree is important as it could get infected with pests and physiological imbalances might occur in the tree. Leaf scorch and premature fall coloration and early leaf drop are a few noticeable imbalances in transplanted trees.

Can trees be integrated into infrastructure?

Integrating trees into infrastructure is the most preferred method over transplantation, according to experts. Appari said, “Curving roads slightly to avoid trees, designing tree houses around them, or creating holes in structures to allow trees to grow through – architects should think out of the box to include trees and not remove them in the design.”

Designing projects to complement and integrate existing trees at the site is possible if all the stakeholders – property owners, surveyors, architects and engineers are dedicated to the idea. “Generally, property-owners do not ‘see’ trees, surveyors depict them as small icons, architects are trained to ‘build buildings’ and engineers see trees as encumbrance, preferring to remove them from the site to ease construction. It is assumed that trees can always be planted later, that old ones can be replaced by saplings,” said Moulshri Joshi, founding partner of Delhi-based design practice SpaceMatters.

While designing a school in Berasia, Bhopal, part of the CM Rise project of the Government of Madhya Pradesh, SpaceMatters wrapped the junior school around the existing trees at site, “despite having a master plan that wove the building around existing trees, we had a situation when portion of the building foundation fell too close to an old Mahaneem tree. We revised the design, redesigned the footings to ensure that the concrete is not cutting the roots and trimmed it slightly to grow away from the building into the courtyard. Thanks to that tree which survived and now stands tall in the court, the children will return to a new building with old trees preserved.”

Embracing trees in the infrastructure is possible by thorough analysis of the species and its ecosystem. “Do the roots damage the building? If the building is too tall or too close to the tree, the tree may not survive. We need to design with empathy and awareness,” Joshi added.

Banner image: Tree transplantation in Kerala. Image by Anish Nellickal via Wikimedia Commons (CC BY-SA 4.0).

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Aditi Tandon Senior Production Editor

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Cities and TownsConservationDeforestationForestsTreesIndia

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