What is the Role of Forests in the U.S. Carbon Balance

U.S. forests play a large role in offsetting carbon emissions, about 20 % of the U.S. fossil fuel carbon output. If a forest replaces itself after a disturbance like fire, then there is no long-term loss of carbon.

Mike Ryan
USDA Forest Service Rocky Mountain Research Station

Producer - Michael Furniss
Videography - Ben Nieves
Technical production - Jeffrey Guntle

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Forests matter in the global and U.S. carbon cycle because they store much carbon in wood, dead wood, and soil and because this storage can be easily changed. Currently, forests and long-lived wood products annually store 313 million metric tons of carbon per year (1 million metric tons = 1012 ), which offsets about 20 percent of U.S. fossil fuel output of 1580 million metric tons of carbon per year. Woodland expansion onto grasslands offsets another 120 million metric tons of carbon per year. 


The large U.S. carbon sink is likely the result of recovery from past heavy wood use and logging, but increasing CO2 and nitrogen deposition may also be increasing productivity. Forest carbon goes through a predictable cycle after a disturbance, with losses either during or after the disturbance and recovery with regrowth. As long as forests replace themselves and the frequency of disturbance does not increase dramatically, forested landscapes are very resistant to changes in carbon over the long term. However, if tree regeneration is unsuccessful after disturbances such as fire, insects, or storms and the forest changes to meadow or shrubland, then the carbon stored in the former forest is lost to the atmosphere.

You should gain an understanding of:: 

How emissions from forest disturbance are affecting the carbon cycle.

The important role of tree regeneration after a forest disturbance, in terms of maintaining forest carbon storage.