ForWarn II

Satellite-Based Change Recognition and Tracking

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ForWarn provides near-real-time tracking of vegetation changes across landscapes in the United States. Useful for both monitoring disturbance events as well as year-to-year variability, derived products can also be used to develop insights into seasonal and inter-annual dynamics.

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Forest Change Assessment Viewer

The Forest Change Assessment Viewer provides a vegetation change recognition and tracking system for ForWarn that uses high-frequency, moderate resolution satellite data.

Recent News

07/06/2022 - 13:15
View ForWarn III, Sentinel-3-based forest change products now in ArcGIS Online (AGOL). No ESRI account required, use this AGOL web map 'as is' or add other data layers from your agency's' AGOL...
06/30/2022 - 08:57
ForWarn 'II' uses NASA's MODIS satellite imagery. Currently, NASA MODIS have not supplied source imagery since May 24, 2022. ForWarn II production using this data stream has been discontinued....
06/30/2020 - 10:36
2020. Norman, Steven P.; Christie, William M.. Chapter 7 - Satellite-based evidence of forest stress and decline across the conterminous United States for 2016, 2017, and 2018 (https://www.fs.usda....


Welcome to ForWarn II!

ForWarn II has enhanced sensitivity, now showing even slight disturbances earlier than ever before, and now covers a larger geographic area.

ForWarn II is mostly the same system with which you're already familiar, but now has a totally new production system that offers some exciting new capabilities, including some new products designed for specialized purposes. For example, disturbances within grasses, shrubs and other shallow-rooted vegetation can sometimes dominate the disturbance signal seen in ForWarn maps, particularly in the Western United States. Almost every ForWarn II disturbance map now has a "Muted Grass/Shrub" companion product that concentrates on the disturbance responses of trees, reserving more of the dynamic range in the maps for showing forest impacts.

Most new ForWarn II products are already available for the entire MODIS period starting in 2003 to present. Most of the data viewer features, like the Share-This-Map, the NDVI graphing tool, and the PestProximity tools, will still work just as always. Documentation is still being developed, so please pardon our virtual dust as we continue to carry these improvements throughout the entire Forest Change Assessment Viewer 2 and the ForWarn II website. Enjoy the new features, and we welcome your feedback!

Hurricane Florence moves toward landfall in North Carolina

Hurricane Florence soaks the South

Hurricane impacts to forests can vary greatly depending on the qualities of the storm. Hurricane Florence stood out for its slow speed and heavy rainfall to the Carolinas, while Hurricane Michael, that crossed Florida's panhandle just a few weeks later in 2018, was a... read more »

Hurricane Michael damage to coastal forests

Hurricane Michael storms Florida's panhandle

The destructive impacts of Category 4 Hurricane Michael on the forests of northwest Florida were captured by ForWarn II's routinely produced Early Detect product one week after the event. The stark pattern of greatest damage in red and orange consists of a 50 km-wide... read more »

Hail storm damage to corn and soybeans from Sentinel 2

ForWarn II maps hail damage to Midwestern crops

ForWarn's all-lands approach to monitoring provides valuable insights into crop damage caused by summer storms. In July and August of 2018, hail storms struck eastern Nebraska causing severe damage to corn and soy.

Remote sensing provides an invaluable way to... read more »

Gypsy Moth defoliation was extensive in 2015 in northeastern Pennsylvania

Tracking Gypsy Moth emergence and severity with magnitude and duration

Remote sensing is adept at identifying and qualifying many forest disturbances, but there remains a substantial need to further quantify actual impacts in many cases. Traditionally, vegetation change-detection approaches, such as that used by ForWarn, identify and... read more »