Standing tall, proud and glorious in the sun, it is hard to believe that the magnificent eucalyptus has a sinister side, silently depleting groundwater resources and disrupting ecological balance.
With Seemai Karuvelam trees at the centre of public outrage, the eucalyptus escaped in its shadow, although the Madurai bench of the Madras High Court ordered the government to get rid of exotic species like wattle, eucalyptus and focus on restoring Shola grasslands.
While Seemai Karuvelam was widely accused of being aggressive invaders of natural vegetation, experts say effects of indiscriminate eucalyptus plantation could be worse. “I don’t see why Seemai Karuvelam is drawing flak, when the eucalyptus is being promoted as an industrial species. Both have terrible effects on the ecosystem,” said D Narasimhan, head of Botany department at Madras Christian College.
Eucalyptus absorbs more groundwater than Seemai Karuvelam, he added. It consumes about 10-15 litres a day, and its roots spread six feet into the soil. Although it supports ground vegetation to an extent, as opposed to claims to the contrary, Narasimhan said eucalyptus leaves have allelopathic properties that inhibit germination and survival of certain other organisms.
According to a study by Calder et al, in Hoskote in the Bangalore Rural district, it was found that water used up by eucalyptus plantations was 3400mm over three years, compared to rainfall of 2100mm over the same period. S Parameswarappa, retired Principal Chief Conservator of Forests, Karnataka Forest Department, was part of the study.
GS Dhanapathi of the Farmers Forum of India, who has been fighting for the elimination of Seemai Karuvelam and eucalyptus, said that while farmers like him were already in the red with the severe water crisis in the State, saving whatever groundwater was left was of utmost importance. “Eucalyptus patches are even unfit for cattle to graze,” he said. These tress are said to have toxic properties that affect goats and cattle.
Not always was eucalyptus seen as the villain. Plantations were on a large scale, originally to bridge the gap in the demand and supply of pulpwood. Three years before the Tamil Nadu Newsprint and Papers Limited was set up in 1979, this demand was estimated to be 17 million m3 by the National Commission on Agriculture. The supply was merely 4 million m3. And Eucalyptus globulus, one of 800 species in the genus, was taken up for regular plantation to satisfy the requirement of firewood.