How do forests store carbon dioxide, and how much of it do they keep out of the atmosphere

Carbon dioxide is taken in through leaves as part of photosynthesis, the process which produces the sugars that fuel the growth of trees. Excess oxygen is released through the leaves, and the carbon from the sugars becomes part of the tree's living tissue, called the cambium. During each period of growth, the old cambium forms a new ring of wood, thickening the trunk, and more carbon dioxide is taken in to form another layer of living tissue. Carbon is also stored in the earth, as dead leaves, branches, trees, and other vegetation partially decompose and create more topsoil.

According to a 2006 report from the UN, forests store about 312 billion tons of carbon in their biomass alone. If you add to that the carbon in deadwood, litter, and forest soil, the figure increases to about 1.1 trillion tons! The UN assessment also shows that the destruction of forests adds almost 2.2 billion tons of carbon to the atmosphere each year, the equivalent of what the U.S. emits annually. Many climate experts believe that the preservation and restoration of forests offers one of the least expensive and best ways to fight against climate change.