Both locally and globally, the forest stands in close interaction with the environment. Forests contribute significantly to oxygen generation and carbon storage. The temperature-regulation effect a forest has on its surrounding environment is a reason why city parks or green areas are especially popular on hot summer days. Forests and forest soils act as filters, oxygen producers and water storage areas.
A tree produces its biomass, like all green plants, practically out of "nothing", i.e. carbon dioxide, water and solar energy. In India, the forests contain 2,800 million metric tonnes of carbon in living forest biomass, making it easy to envision exactly how forests serve as the “green lung” of the country and of the world.
A 100 year old oak tree with 130,000 leaves, their biological cells, binds about 5,000 pounds of carbon dioxide to organic substances such as wood, leaves and bark each year and gives off up to 4,500 kilograms of oxygen, which is the annual requirement of eleven people. At the same time, the tree works as an air conditioner. The roots of that oak absorb about 40,000 liters of water from the soil every year, then "sweats out" via the leaves again. The generated evaporative cooling ensures that the forest even on hot summer days remains pleasantly cool. In addition, it filters about one tonne of dust and pollutants from the air, thus acting like a giant vacuum cleaner.