Burning virtual trees to save forests

The Green Knoll fire at Jackson Hole, Wyoming, is shown in these images captured by the Terra satellite's Multi-angle Imaging SpectroRadiometer, or MISR, on July 27, 2001.

By Amanda Barnett
CNN

(CNN) -- We've all heard the old expression about fighting fire with fire, but how about preventing fires with satellites and computers?

Scientists are using satellite imagery to create maps for computer programs that simulate lightning strikes on virtual forests.

"Having a digital map of forest characteristics and simulating the fire behavior of the whole map in a computer is really the future of planning efforts," said Mark Finney with the U.S. Forest Service's Missoula Fire Sciences Laboratory in Missoula, Montana.

Finney developed FARSITE, a fire simulation program that computes fire growth and behavior for different terrains and weather conditions.

Controlling, not stopping fire

The goal isn't to prevent all fires. Forest managers say some fires keep underbrush in check and open up seed pods.

By simulating the spread and intensity of wildfires, the managers hope to better determine when to intervene to prevent fires that could rage out of control, killing everything in their paths.

Intervening may mean simply trimming branches and clearing brush. Or firefighters may set controlled burns to use up fire fuel.

Last year, federal agencies set 4,651 prescribed fires and burned more than one million acres, according to the National Interagency Fire Center's Web site.

But these burns can be controversial and dangerous. In May, 2000, a prescribed fire in Los Alamos, New Mexico, burned out of control after the National Park Service set it to clear brush at the Bandelier National Monument. The fire burned 47,650 acres and destroyed 235 residences, according to the NIFC. It led to a temporary moratorium on prescribed fires.

"In the Los Alamos fire, the big problem was that fire managers guessed how the fire would spread, and they guessed wrong, so the fire burst out of control," said Steve Running, a forest ecology professor at the University of Montana who specializes in remote sensing applications.

Better models mean better options

Computer models help forest managers evaluate conditions before they set prescribed burns. And having good models means having better options.

A drawing of the Terra satellite

That's where satellites come in. Landsat 7, which has been mapping the Earth for years for the U.S. Geological Survey, helps produce "virtual landscapes." The 30-meter resolution maps produced by the satellite provide information about the density of vegetation in forests. The Landsat data is added to a digital map to create a 3-D landscape.

Another NASA satellite, Terra, also is helping firefighters. Terra's Multi-angle Imaging Spectro-Radiometer, or MISR, can create nine different views of the terrain below, allowing scientists to see the forest -- and the trees -- from different angles.

Finney estimates that about 40 percent of forestry managers now use some type of high-tech tools. But he predicts usage will increase as computers get faster and the models get better.