Forest contributes to carbon sequestering by storing carbon dioxide from the atmosphere and turning it into biomass through photosynthesis.  After then sequestered carbon builds up in forest soils, biomass, deadwood, and litter. Natural processes like respiration and oxidation as well as intentional or unintentional effects of human activity like harvesting, fires, and deforestation cause the release of carbon from forest ecosystems.

The contribution of forests to carbon cycles must be assessed while also taking into consideration how harvested wood is used such as in the production of wood products that store carbon for a specific amount of time or energy that releases carbon into the atmosphere.

Forests help to reduce carbon emissions by serving as both a carbon reservoir and a mechanism to sequester more carbon when the net balance of carbon emissions by forests is negative. When there is a surplus of carbon emissions, trees help to accelerate the greenhouse effect and climate change.

The tree effectively breaks down the carbon dioxide, stores the carbon in all parts of the tree, and release the oxygen back into the atmosphere. Fast-growing trees are, in fact the most efficient way to sequester atmospheric carbon.