The main problem is trees are being cut to make way for infrastructure, especially on the roads. The largest trees lost are on roads, and the biggest trees are those that were planted in the 1980s when a massive tree plantation drive was undertaken. It is also the largest trees that are being cut, with the largest canopies that are capable of reducing pollution and temperature. Realistically, it takes about 20 years for trees to grow that big.
What we can do now is to save trees. For example, road alignments set for widening can be changed by choosing a parallel road or changing the bend of the road slightly. This way, even with expansion of infrastructure, trees can be saved.
The other thing is to plant compensatory trees. Unfortunately, ornamental trees are being planted wherever there is such a compensatory plantation. Places that have a lot of trees are those that the public cannot access, such as Army campuses.
The third thing we need is documentation. A tree map is needed. Right now we have only estimates. We have been trying for a long time, but there has never been a tree census.
Planning doesn’t factor in trees. Even the Bruhat Bangalore Mahanagara Palike civil engineering plans include only seeking permission for cutting trees, but not any joint consultation with other departments to avoid cutting trees.
What we need is a proper tree policy that says what trees to plant where. For instance, drumstick trees can be planted in slum areas or small layouts with narrow streets, while banyan and peepal trees can be planted on larger roads. Even tamarind and mango trees can be planted instead of the ornamental ones. Local people need to be consulted as well, as it is very ad hoc right now.