Deccan Chronicle 18.02.2010

City swelters: 10º hotter without trees

Feb. 17: With the ‘Garden City’ becoming an IT hub, tree-lined avenues have begun to give way to highways and flyovers. But it does not bode well for the pleasant climes Bengaluru is known for, according to a survey conducted by Ashoka Trust for Research in Ecology and the Environment (ATREE). The findings of the ‘Street tree of Bengaluru: A critical ecological and environmental resource’ survey conducted between July and August in six places including Hennur Junction on Outer Ring Road, Magadi Road and Mekhri Circle has shown that stretches of roads where trees have been cut off are 10 degree Celsius hotter than those lined with trees.

That is not all. These roads are more polluted, with their levels higher than national standards and have registered a steep rise in the presence of suspended particulate matter (SPM). On Sarjapur Road, where trees were felled recently to widen roads, the level of sulphur dioxide was 200 per cent higher than the average standard.

Roads with trees were found to be 20 per cent more humid, making it easier to tolerate the heat. “The survey proves that trees reduce temperature, increase humidity, absorb sulphur dioxide and remove suspended particulate matter. This survey was, however, conducted in monsoon. We will be doing a survey again during the peak of summer,” said Harini Nagendra, urban ecology coordinator of ATREE, talking at a session held at IISc on Tuesday.

“The city is transitioning to an urban structure dominated by roads. With no policy in place on tree planting, there is no clear direction on what kind of trees Bengaluru actually needs. The trees that are being planted by BBMP on the streets are short and will change the look of Bengaluru’s landscape for the worse over the next 15 years. Instead, BBMP can plant tamarind and mango trees, which will also yield a certain amount of revenue for the agency,” Harini added.