Satellite-Based Change Recognition and Tracking


Spring defoliations emerge like measles during 2010; Image: Steve Norman, USFS.

Defoliation on the bayou

Spring often brings defoliating insects to the forests of Louisiana. In this image from early May 2010, defoliations from forest tent caterpillars and baldcypress leafrollers create an erupting "measles-like" pattern. Note the subtle differences in severity outward from... read more »

Drought, beetles and fire in Colorado

Since 2004, southwestern Colorado's Englemann spruce forests have experienced a severe outbreak of spruce beetles (Dendroctonus rufipennis). Such outbreaks occur episodically, multiple times per century (Anderson et al. 2010). Early research in northern Colorado linked a... read more »

A multi-year view of Sudden Oak Death

Sudden Oak Death (SOD) is a disease caused by the new pathogen Phytophthora ramorum (Frankel and others, 2013). This spore-producing water mold was first observed when tanoak trees began dying during the mid 1990s in California’s Marin and Santa Cruz Counties. SOD is now... read more »

Hemlock death transforms Appalachian forests

Across the Southern Appalachians, Eastern Hemlock has long created an important ecological niche. As these trees are evergreen, they provide year-long cover for wildlife and they cool riparian areas where they tend to grow. Since the mid 2000s, these forests have been... read more »

Monitoring Gypsy Moth defoliation in near real time

By late 2012, forest health monitors in western New York and Pennsylvania knew that they were about to experience a severe outbreak of the non-native Gypsy Moth. Surveys showed an unusually high density of egg masses on the branches and trunks of trees, but neither egg... read more »

Tracking the historic Rim Fire

The 2013 Rim Fire burned over a quarter million acres of California's Sierra Nevada, including a portion of the Stanislaus National Forest and Yosemite National Park. It started in mid-August as an illegal campfire after an unusually dry winter and spring. A lower-than-... read more »

An ephemeral wind or hail disturbance in northeastern Tennesssee. Image: Steve Norman, USFS.

Tracking the ephemeral in Tennessee

Full-fledged tornadoes are typically well documented, but the massive outbreak of April 2011 also had localized short-term effects that are easily overlooked. This image pair from a month after the storm (top) and two months later (bottom) shows how fast seemingly severe... read more »

The 2011 Springfield tornado. Image credit: Steve Norman, USFS

Tornado tears through Massachusetts

A severe tornado touched down near Springfield, Massachusetts on June 1, 2011, then carved a path through nearly 30 miles of state and private forest. The streak in red show an extreme reduction in growth compared to the prior year’s condition as of mid-June. Many of the... read more »

Snowpack drives greenup in the Sierra

Year to year variation in climate has been extreme in California's Sierra Nevada. In particular, low winter snowpack raises concerns about municipal water supplies as reservoirs are fed by spring meltwater. However, low winter snow cover has implications for the region's... read more »

The Great Smoky Mountains tornado

The April 27, 2011 tornado that hit Great Smoky Mountains National Park in eastern Tennessee was a powerful EF4 storm (its direction is indicated by the black arrow). Wind storms are important natural disturbances for Southern Appalachian forests, and the ecological... read more »

Dead pines from drought in Houston; Photo credit: Ron Billings, Texas Forest Service

Drought takes a toll on Texas trees

The forests of Texas continue to suffer through one of the most extreme droughts on record and a large number of trees have already died. The photo shows mortality in Memorial Park, Houston (Ron Billings, Texas Forest Service). By late August of 2011, the regional... read more »

Hail defoliates the City of Asheville, NC watershed

Hail pellets a city watershed

The spring of 2012 was exceptional across much of the eastern US because it occurred weeks earlier than normal. Yet some forests also experienced strong spring hail storms that left leaves in tatters and set spring growth back. Forwarn successfully captured this... read more »

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What is ForWarn?

ForWarn is a satellite-based forest disturbance monitoring system for the conterminous United States. It delivers new forest change products every eight days and provides tools for attributing abnormalities to insects, disease, wildfire, storms, human development or unusual weather. Archived data provide disturbance tracking across all lands since 2000. Interactive maps are accessible via the Forest Change Assessment Viewer. Read more about ForWarn here.

Recent News

04/02/2014 - 09:55

The ForWarn team received a Chief's Honor Award from U.S. Forest Service Chief Tom Tidwell at a ceremony held on March 17 in Washington, D.C. William Hargrove, Eastern...

01/09/2014 - 15:18

USDA Forest Service Chief Tom Tidwell has announced the winners of the 2013 Chief's Honor Awards. The ForWarn team, including scientists and staff from the...