Indiscriminate toppling of trees in the capital and other urban areas during storms and rains poses a threat to life and environment.
Urban areas are losing a few more trees almost every time due to storms in tropical weather.Experts said unscientific tree plantation and lack of monitoring and concretes around roots are responsible for tree toppling during storm and rain.
Md. Yousuf, divisional forest officer of Dhaka Division, told the daily sun that one of the reasons behind toppling of so many trees during the storm was selection of wrong varieties of trees in an urban setting.
Short-rooted trees planting in urban and roadside areas is responsible for toppling in a weak storm or gusty wind, he said, adding that roots of trees did not grow enough for their stability due to concrete on the both sides of tree.
All trees grow some roots parallel to the surface, parts of which stick out of the soil. The roots growing on the surface play an important role in holding the trees firmly.
Unbalanced pruning is also one of the reasons behind falling of big trees, he said. Sometimes branches on one side of trees are chopped off while their other side remains untouched which is unscientific, because one side becomes heavier than the other side of the trees, said the forest expert.
“Concrete does not allow the tree roots to go deep down onto the soil. So, the trees turn weak and fall prey to strong wind,” he said.“Choosing right type of trees for planting in urban zone is important and the authorities concerned should engage Botany experts to identify the reason of tree-toppling,” he added.
Each and every year different organisations dig roads and roadside pavements snapping roots of trees, resulting in their toppling.
Gowhar Nayeem Wahra, a disaster expert, said: “Most trees that fell down during storms are of foreign origin. They are Chambal, Acacia, Ipil Ipil and Krishnachura. Roots of these trees do not go deep into soil. But, no tree of local origin fell down or uprooted during storms,”
He said most of the long trees in Dhaka are not deep-rooted and they come from foreign origin and at the same time they are not suitable for planting along roadsides or pavements.
“Most of the trees that fell down during storms were planted on islands, road dividers and roadside footpaths in a small ground of soil portion,” he said, adding that their roots did not spread enough to hold the trees.
A number of big trees toppled on the streets in many parts of the capital, slowing down traffic during rush hours following a nor’wester that lashed the area on March 31.
A woman was killed as a tree uprooted in Parlaiment area during that storm while a private car and a three-wheeler were also stuck under a branch of a falling tree in Kakrail, a falling branch of a tree blocked the road in Dhanmondi and a tree collapsed on a private car and a auto-rickshaw in Gulshan-2 on the day.
On May 18, a sudden storm ripped out trees from their roots at several places in the capital suspended a number of roads during the time.
On April 8, a giant tree uprooted on a private car in Banani area.
Aminul Islam, chief estate officer of Dhaka North City Corporation, said many trees uproot and branches break down during storms in the city each year.
They clean the uprooted trees and branches after a storm, he said.