The eucalyptus plantations of the Nilgiris, which have for long been considered "ecological predators," will be replaced in a phased manner by trees belonging to the shola species which are "rainwater and ground water-friendly ". Inaugurating a seminar on 'rainwater harvesting' in Tamil Nadu, the collector, Supriya Sahu, said that within 10 years the green cover in many parts of the district would undergo vast changes for the better.