Hebbal tunnel plan to fell 1,128 trees spanning over 70 species, experts warn of heat islands

More than 70 tree species stand among the 1,128 trees marked for felling along the 2.2-km corridor of Bengaluru's proposed Hebbal short tunnel, a tally that experts say points to significant biodiversity loss and a likely rise in local temperatures.

Documents from the Greater Bengaluru Authority (GBA) list species including Indian Kino, Big-leaf Mahogany, Beleric Myrobalan, Indian Jujube, Maple-leafed Bayur Tree, Paper Mulberry and Yellow Tabebuia. The count of species could rise further, as the GBA has not yet put out the filtered list for public review and objections.

The number of trees to be removed was initially put at 1,400. Officials said a few hundred have since been marked for retention because they do not fall within the tunnel's alignment.

Climate and habitat concerns

R. Ganesan, an Adjunct Fellow at ATREE, said such species richness within a 2-km stretch is uncommon in an urban setting, though not unheard of. He noted that while forests often pack many species into a small area, the figure in a metropolis like Bengaluru reflects years of retained green space, and that the Hebbal area has already seen considerable environmental damage. The felling, he said, will have a direct effect on temperature.

Former forest secretary A.N. Yellappa Reddy said removing over 1,000 trees would destroy habitats and oxygen banks and affect underground water levels. He estimated that temperatures in the immediate area would climb by at least two degrees and create heat islands, with the warming extending roughly 2 km beyond as a ripple effect. Birds, squirrels and garden lizards would move away, he added, and the loss of so many species would take multiple ecosystems and habitats with it, denting quality of life.

Objection window questioned

The GBA issued a public notice on September 20 inviting objections to the felling and said details of the trees and their locations had been posted on its website. Three days later, the list had still not appeared.

Environmental activist Dattatraya Devare called the handling of the objection process negligent, arguing that without the details the public cannot frame specific objections, and that vague objections risk being discarded. He urged the authority to re-issue the notice after publishing the list and then invite objections afresh. Other citizen groups have also sought the immediate release of the details.

Petition gathers signatures

A petition opposing the Hebbal Short Tunnel project has crossed 20,000 signatures, with signatories calling for a pause and independent assessments of its environmental, hydrological, traffic and safety impacts.

Launched on Change.org on August 3 under the banner "Save Bengaluru's Green-Blue Landscape", it raises concerns about the ₹1,140-crore, 2.2-km cut-and-cover tunnel, which is expected to pass through areas including the Hebbal lake buffer, Hebbal Tree Park, the Veterinary College campus and UAS staff quarters.