Botanists has said that the reason behind a number of trees being uprooted after the showers on Monday and Tuesday in Pune is mainly due to damaged roots and limited space for the trees to spread out.

About 40 trees were uprooted in the Pune Municipal Corporation's (PMC) limit and there are about 150 reports in total about fallen branches and uprooted trees. The construction and tarring of roads might have caused damage to the roots making them weaker.

Experts said that exotic trees fell because of their shallow roots and others didn't have the space to spread out roots. Last year too about 150 trees fell after heavy rainfall in November and most of these were exotic trees that were unable to adapt to local conditions and had smaller roots.

A known botanist S D Mahajan has said in his book, Aapale Vriksha that exotic species of plants disturb ecosystem while native trees are very important for the local flora and fauna. They attract birds, butterflies and increase food and habitat, he said.

The construction activity near the trees cut their roots and thus they fall during heavy rains or fast winds. The trees on the roadsides also lack the adequate space to spread out their roots and hence are prone to being uprooted.

"The non-native trees grow fast but the roots are shallow and prone to falling. But citizens plant exotic trees because of their beauty and quick growth," said Ketaki Ghate from the Ecological Society. She further said that when new roads are being planned the trees should be given adequate space to spread roots.

Most of the trees that fell after the rainfall this week were roadside trees further indicating this problem. The Pune Municipal Corporation's garden department head Bhanudas Mane said that people should consider sapling, place and the distance while planting trees. He indicated that most of the new trees plant this year would be local species.