Forest disturbance monitoring tool | ForWarn

U.S. Forest Service EFETAC
Detail of a map from the Forest Change Assessment Viewer, part of the ForWarn website

Forests and vegetated landscapes change naturally through the seasons. However, dramatic changes that occur at unexpected times can be detected through satellite imagery. Forest and natural resources managers, decision makers, scientists, and the public can use this system to understand potential threats to our nation’s lands. »


NEMAC has supported the U.S. Forest Service’s Eastern Forest Environmental Threat Assessment Center in the development of a cutting-edge forest disturbance monitoring system called ForWarn. Other partners include the Western Wildland Environmental Threat Assessment Center, NASA, the U.S. Geological Survey, and Oak Ridge National Laboratory, among others.

Forest Change Assessment Viewer

The Forest Change Assessment Viewer is a map application that allows the user to directly interact with many different datasets, layering them in order to uncover trends in forest change.


Accurate interpretation of the cause or causes of a forest change or phenological patterns requires supportive information. Many of the datasets available in the Assessment Viewer are products that have been produced by a number of trusted sources, including NOAA, NASA, the U.S. Forest Service, and other state and local entities. 


Learn more about disturbances and change events that have been documented using ForWarn on the ForWarn website. Examples include insect outbreaks, tornadoes in the Southeast, and the drought of 2011.

Training Videos

Visit ForWarn’s homepage for access to various training videos on how to use the Assessment Viewer and an overview of the ForWarn project.