Importance of trees

In one day a human being breathes oxygen equivalent to three cylinders.Each oxygen cylinder on an average costs Rs 700, so in a day one uses Oxygen worth Rs 2100 and for a full year it is Rs 7,66,500.
If we consider an average life span of 65 years; the costs of oxygen we use become a staggering sum of Rs 500,00,000. All this oxygen is derived free of cost from the surrounding trees. Very few people look at trees as a resource and there is rampart tree cutting going on everywhere which should stop.