Disturbance Events Map
Browse some of the verified and potential forest disturbance events captured by the ForWarn tracking system.
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.
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.
Hurricane impacts to forests can vary greatly depending on the qualities of the storm.
ForWarn’s ability to accurately map defoliation comes from the high temporal frequency of the source imagery (MODIS).
Remote sensing technologies provide an increasingly efficient way to monitor large tracts of forest canopy conditions in near-real-time and seasonally.
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.
The Forest Tent Caterpillar (Malacosoma disstria) is a widespread native defoliator of deciduous forests in the Eastern US.
The Pandora Moth (Coloradia pandora) is a native defoliator of ponderosa, Jeffrey and lodgepole pine trees of the Western US. During most years, populations and defoliation is minor, but periodic outbreaks cause widespread defoliation (Speer and others 2001).
Urban areas are renowned for their admixture of species and vegetation types that can change from one parcel to the next. Yards and woodland parks intermix with road medians--all of which may be dominated by an irregular mix of native and exotic trees, shrubs, herbs and grasses.
Understanding the normal start of greenup for croplands is important because it provides a baseline to compare year to year conditions.
The start of the annual growing season is among the most important climate-sensitive measures that Land Surface Phenology (LSP) products like ForWarn can provide.
It can be challenging to detect disturbances during seasonal periods of transition such as Fall or Spring in the eastern deciduous forest.
Coastal forests and shrublands can be vulnerable to climate-associated disturbances such as the strong winds and storm surges associated with hurricanes.
During the first week of June 2014, hail caused significant damage to corn and soybean fields in eastern Nebraska and western Iowa.
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.
ForWarn's true color product is produced every 8 days at 1km resolution to provide a quality control for ForWarn's disturbance maps. Clouds and snow cover that persists for the entire 24-day MODIS collection window can create the appearance of vegetation disturbance, when it is not.
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 forests as well.
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.
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).
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.
In early September of 2013, unusually heavy rain resulted in catastrophic flooding across Colorado’s Front Range and downstream along the South Platte River. Rainfall exceeded 20 inches northwest of Denver, which is close to the average rainfall for that area during an entire year.
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.
ForWarn's standard calculation of the current state of vegetation is based on the maximum NDVI value observed for each 24 day period. This standardized window is needed to minimize the chance that clouds or other atmospheric effects will cause misleading results in the change product.
Land managers in the West seek to efficiently monitor their forests and rangelands, particularly after wildfire. ForWarn's high frequency record of the Normalized Difference Vegetation Index (NDVI) provides a coarse filter means to accomplish this using two measures.
Hurricane Sandy, one of the most damaging hurricanes to strike the United States, tested the monitoring ability of the ForWarn system. Detecting any disturbance is difficult during the spring and fall because vegetation is actively changing due to normal seasonal dynamics.
ForWarn's MODIS satellite-based products go back to 2000, and this allows us to observe the effects of wildfire and recovery since early in the decade.
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's ability to capture short and long-term change is shown by this animated image pair that provides two different temporal contexts for the same date in May of 2012. The "all year" baseline shows change since 2000.
Over the last 15 years, Mountain Pine Beetles have killed large tracks of ponderosa pine across the Black Hills of South Dakota. Beetles thrive with continuous stands of dense trees, and decades of fire exclusion have led to that landscape and stand-level condition.
Across Texas, 2011 will long be remembered as the year that the trees died.
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.
This late April 2010 image shows a large anomaly just east of Lake Ontario on the Tug Hill Plateau of New York. A less severe area of departure from the prior year’s condition occurs to the east.
Outbreaks of the defoliating pine butterfly are rare. In eastern Oregon, outbreaks occurred in 1908-11, 1940-43, 1982 and from 2008 to 2011. Sometimes defoliations can lead to mass mortality of ponderosa pine—the primary host, but not always.
The Atchafalaya basin's forests thrive with seasonal flooding, yet high water is normally a spring phenomenon there. During the past month, unusually high water levels have inundated wetlands and forests along and near the Mississippi River basin.
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).
This fall 2011 webworm outbreak in the Hickory Creek Wilderness Area of the Allegheny National Forest, Pennsylvania stands out against the near normal (blue) background that dominated the state in early fall.
In September of 2011, the Pagami Creek Fire burned over 92,000 acres in the Boundary Waters Canoe Area Wilderness (BWCAW) of the Superior National Forest, Minnesota Much of this burned at high severity, as indicated on the October forest change image.
A sizable portion of the Wenatchee National Forest, Washington shows less vegetational vigor than it did at its peak of the last decade.
Substantial forest area has fallen to development in the periphery of many urban areas over the last decade. The image below shows deforestation in the periphery of Raleigh, NC as yellow to red anomalies. Blue areas have not changed during the last decade.
On April 24, 2010, a lethal F4 tornado struck the forests east of Yazoo City, Mississippi. Within a few weeks the path of the storm and patterns of severity are clearly shown with this comparison of conditions relative to the same time in 2010--the year before the event (top image).
This image shows forest change anomalies on the north slope of the Wasatch Range of Utah on September 13, 2011 compared to the prior year. The high elevation zone above treeline is shown as an uncolored area under the words “Wasatch Range”.
Deforestation for strip mining is common practice in the coal regions of eastern Kentucky, Virginia and West Virginia. The image below shows areas where forests have been removed for mining over the last decade (left).
This before-after image pair shows changes associated with Hurricane Irene. Its path is shown by the bold blue line. In the pre-Irene image (left) shades of green and yellow show the effects of drought on vegetation and dark red spots are recent wildfires.
In June, the Wallow Fire burned over half a million acres in east-central Arizona, much of it on the Apache-Sitgreaves National Forests. A substantial portion of the burn area was of high severity, killing millions of trees outright.
Georgia’s Okefenokee Swamp National Wildlife Refuge near the Georgia-Florida line burned in 2007 and again in 2011. This rapid recovery of fuels reflects the importance of sprouting vegetation. In the map sequence from the summer of 2011, this resilience is clear.
The Pains Bay Fire was started by lightning on May 4, 2011 in the peaty soils of North Carolina’s coastal plain. By the end of June, the fire was contained, but the deep soils continued to smolder for weeks. The white line marks this 45,000 acre fire’s final perimeter.
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.
According to climate data, coastal North and South Carolina were having a mild drought in mid May of 2011.
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).
Full-fledged tornadoes are typically well documented, but the massive outbreak of April 2011 also had localized short-term effects that are easily overlooked.
Forests across northern Mississippi, Alabama and Georgia were hard hit by tornadoes in April, 2011. Tree mortality was often severe for areas in the direct path of these storms as shown in this photo from near Lake Burton in the Chattahoochee National Forest, Georgia (top).
Other Disturbances Assessed
Emmett Ranger District
"Area was hit hard by gypsy moth caterpillar defoliation for the third year in a row. We mapped it during this years aerial survey and ground truthed the area last week to confirm gypsy moth as the primary defoliation agent".
There was no response received to initial email inquiry.
Areas east of Sault Ste. Marie, Ontario, Canada. Agent appears to be active eastward to New Brunswick to n. Maine.
"The disturbance in this area has been reported at hail damage".
Forest defoliation by baldcypress leafroller and forest tent caterpillar detected in these southern Louisiana counties: Ascension, St. James, Assumption, n. Lafourche, n. Terrebonne, St. Martin and e. Iberia County.
ForWarn has potentially identified an area of change in the Southern Appalachians sometime between 2010 and 2012, which may be attributed to Rhododendron decline.
ForWarn has detected bottomland areas of North Carolina, South Carolina, Georgia and Florida that were affected by Hurricane Matthew in October, 2016. The data shows the intensity of the wetland flooding.
ForWarn has detected a potential double disturbance in portions of Stanislaus National Forest and Yosemite National Park, California in 2015 and 2016. This disturbance may be due to the rim-fire followed by burn land management efforts.
ForWarn indicated that the Chippewa National Forest and surrounding areas had a decline in vegetation greenness due to a storm event on July 22.