Taking the Long View: using satellite images to assess wildfire effects

The year 2000 fire season heightened concern that decades of fire suppression may have lead to larger, more severe wildfires. But in nature, is this unusual? What are the various ecological effects caused by fires of different severity, or even by the variation in severity within particular burns? How do we learn about these effects on a landscape scale? To find out, USGS and National Park Service scientists are looking at fire effects from a unique perspective: Space.

Studies of fire effects on plant and animal communities are currently hindered by the limited availability of standardized, quantitative maps of burn-severity patterns. Remote sensing technologies, such as satellite images, may allow the consistent comparison among sites that this research requires. Where fire size, remoteness, and rugged terrain make alternative methods impractical, remote sensing technologies are highly effective in assessing and monitoring wildfires and their effects.

USGS researcher Sandra Haire and colleagues from biology, hydrology, geology, and mapping are evaluating the utility of using satellite images to develop standardized burn-severity maps for evaluating a number of fire effects and addressing fire management issues. Toward this end, USGS scientist Carl Key developed an index of burn severity called the "normalized burn ratio." The NBR is a method that uses pre-fire and post-fire Landsat satellite images to measure and quantify the ecological effects of fire.

Key works with the USGS EROS Data Center to apply this method nationally to selected large, recent burn areas on National Park Service lands in a variety of forest types from Alaska to the Everglades. The twofold purpose of the research is to develop standardized products for NPS to better understand fire effects and manage for them, and to test the NBR methodology in different ecosystems.

Using the model to examine both pre-fire and post-fire images, scientists are able to distinguish burned from unburned areas, separate recent burns from older ones, and quantify the severity of effects within the burns. With data from Landsat satellite images, USGS researchers can test the ability of burn severity models to help evaluate management decisions pertaining to habitat enhancement, erosion potential, future fire breaks, nonnative plant invasion, biodiversity, fire behavior, and bird communities in many ecosystems.

For more information on the burn severity index technology, visit Fire.org's "Fire Effects Monitoring and Inventory Protocol"

---

For more information, contact:

Juliette Wilson