Pollution causing slow death of trees

Pollution causing slow death of trees
New Indian Express

BANGALORE: It is alarming to note that vehicular emissions have affected tree-growth in the City. Scientist say trees are not only sensitive to pollutants, but show specific reaction to them.

A recent study pointed out at the higher lichen growth on trees, which is a sure bio-indicator of high pollution. Also, the presence of bacteria pseudomonas on leaves affect their physiological activities and can lead to the shedding of leaves.

The study was sponsored by the UGC to learn the effect of air pollution on trees, and was done by a Ph.D student K M Bhoopathi Gupta. He is working under the guidance of Dr R V Rao, Head Wood Properties and Uses Division, Institute of Wood Science and Technology. For this research work, three tree species of African tulip tree, copper pod tree and gulmohar were selected. They were exposed constantly to pollutants in areas like Peenya, Yeshwantpur Circle, Hudson Circle and Mekhri Circle where vehicular traffic is very high.

According to Dr Rao, leaves exposed to pollution are highly prone to invasion by bacteria. A healthy tree will not have accumulation of bacteria.

Moreover, branches of trees collected for study under the microscope, show accumulation of stored energy on leaves. This unused accumulation of starch and protein points out change in internal physiology.

Gupta said that the city’s rapid growth and the resultant increase in number of vehicles are the main cause of air pollution. In these areas, air impurity is high with pollutant gases like sulphur dioxide, hydrogen fluorides, carbon monoxide, ozone and nitrogen dioxide. ”The effect of pollution is based on factors like locality and species adaptability. We will study the variations for atleast two consecutive seasons,” he said.

According to Dr Rao, the study will lead to local and resistant tree species to be mapped according to their resistance to various air pollutants.

“There is a need to find out indigenous species that are tolerant to pollution in urban areas. Later, these trees can be grown as a belt around urban areas to serve like a buffer zone to check and reduce air pollution,” he said. Urban forestry should look at trees that are pollution resistant, wind tolerant and grow trees that are not very tall, he added.