Exotic plants do more harm than good

KOZHIKODE: Contrary to the general perception  that all trees give shade and reduce heat, experts say that the alien trees planted to enrich the forests are actually doing harm to them. While some of them like teak are surface feeders, others like eucalyptus and acacia are depleting the groundwater resources too. Scientists say the forests should be left to flourish on their own, and alien plants should not be planted inside.

According to Kerala Forest Research Institute scientist Dr T.V. Sajeev, the planting of teak saplings in Kerala forests started way back in 1842. “It is difficult to regain the soil quality after teak is planted for a long duration. This destroys the economy and soil at the same time. There is a total plantation of 75,000 hectares in Kerala, in which the 7,500 hectares fall in Nilambur forests alone,” Dr Sajeev says.

He adds that if teak is a surface feeder, plants like eucalyptus and acacia grow deeper and absorb more water. “Since these plants are grown outside the forests and function as shade trees, their actual data is not available with the department. Acacia trees were grown earlier to be used as firewood in an era when LPG was not common,” he added.

The silica content of the teak leaves also damage the soil by reducing its water retention power. The forest department has decided to let the forests regain their capacity and not to grow alien plants in them. The Parambikulam tiger reserve, on an experimental basis, has been selected for the same.