How does carbon offsetting work?
Plants and trees need carbon in order to grow; they obtain it absorbing carbon dioxide (CO^₂) from the air. During daylight hours, by the process of photosynthesis, they convert the CO^₂ into sugars (by bonding the carbon from CO^₂ with the hydrogen from water). The by-product of this reaction is oxygen, which is released back into the air. Some of the sugars are used for everyday use such as respiration; the rest is required for the growth of the plant. Thus a tree and its leaves, branches, bark, trunk and roots consists of approximately 25% carbon. When a leaf falls or a branch breaks, a tree loses some of its carbon that will eventually find its way back into the air as CO^₂. As long as a tree continues to grow, it absorbs CO^₂ which explains the fact that a new forest absorbs so much CO^₂ because the trees and shrubs have high growth rates. A long established forest containing old trees as well as young saplings absorbs about the same amount of CO^₂ as it loses in the process of natural decay. Therefore, an old forest can be said to be carbon neutral because it does not produce any net oxygen. The description ‘lungs of the planet’ is, therefore, more apt when describing new forests rather than long established rain forests.