Forests are constantly changing. To monitor forest health and manage these lands for multiple uses, managers need to understand the processes driving forest change at fine spatial scales over long time spans, because different processes have different impacts on social, economic, and ecological systems.
A collaborative project between the USFS Forest Inventory and Analysis Program (FIA), NASA, and several universities has developed a national dataset mapping the location, timing, and cause of canopy loss events due to removals, fire, stress, wind, and land use conversion, as well as unperturbed forest areas across the conterminous United States from 1986-2010.
The North American Forest Dynamics (NAFD) project is a core project of the North American Carbon Program (NACP). It was designed to use observations from Landsat satellites to clarify the events and processes resulting in forest loss and improve understanding of the carbon budget for the conterminous United States (Goward et al., 2008).
This study used Landsat imagery and a set of algorithms to link forest change event type and timing to more than 258 million hectares of U.S. forested ecosystems. The resulting maps show areas of persisting forest cover loss resulting from land use conversion, as well as temporary losses caused by fire, removals, stress, and wind.
Over 24 years of data, 1986-2010, we find most forest area (71 percent) experienced little to no canopy cover loss. Where canopy cover loss was detected, the vast majority was attributed to temporary removals (81 percent), with only a very small fraction attributed to land use change. This improved characterization of forest cover loss will help support analysis not previously possible across the entire conterminous United States.