Hyderabad: Experts blame the depleting groundwater table as one of the prime causes of trees being uprooted. In the recent thunderstorms, Hyderabad apparently lost around 2,000 trees.
Experts say that when the groundwater falls, the taproots decay and the lateral root system takes over the job of water absorption. The lateral roots, however, do not grow deep and are restricted to a depth of 1-2 meters. In urban areas, trees with deeper roots and narrow crowns are needed to withstand high-speed winds.
“Tree requires water for their survival and in an urban eco system the only water available for the trees is the groundwater table because the concretised top does not allow regular seepage of rain water from the top soil. Thus the trees need to send their taproots deeper down to reach the water table for their survival and growth. If that does not happen, taproots decay and the trees do not have the support, the foundation is weakened and once that happens even low intensity winds can uproot them,” said Dr M. Venkat Rama, Professor of Botany.
The reason for most trees leaning in concretised areas is because when the taproot decays, there is a breakage between the root and shoot system. Because of the weight of the crown (shoot system), the tree then starts leaning as the crown overgrows.
Dr C. Srinivasulu, assistant zoologist - OU and member of TS biodiversity board said, “The policies presently followed with respect to tree plantation or aforestation in urbanized areas, especially in Hyderabad, is unscientific, focus is on fast-growing exotic species rather than the indigenous robust species. In urban eco systems, as the trees are planted along the roads in a single line, species should be carefully and scientifically chosen to avoid disastrous consequences as large crowned species tend to easily fall during gales. Avenue plantation species should preferably have strong root systems with narrow and medium height crown system."
Experts with Telangana State Biodiversity Board say that plantation should be taken up with much care in mind for the environmental help.
