G. Dattatri, Advisor, Nizhal:
One human being requires about 1,30,000 litres of oxygen a year. A large rainforest tree could provide around 2,30,000 litres and a tree in an urban environment about half that much. At least one tree per person is required in that case – an approximate seven million trees for the Chennai Metropolitan Area. To get to this, we have to multiply the present number of trees by four. Trees should not be chosen randomly. Species that are appropriate to the environment and are likely to encourage bio-diversity by attracting squirrels and butterflies should be chosen.