Fire plays an essential role in maintaining healthy forest ecosystems. But decades of suppressing wildfires have caused an unnatural build-up of fuel, leading to more severe fires, increased risk to responders as well as higher costs and property losses.
This ponderosa pine forest shows how fire has played its natural role. The trees are spaced widely enough to allow them to survive low-intensity fires and there is little lower vegetation. (National Interagency Fire Center)
This pine forest has too many young shrubs and trees, which would allow fire to burn hot and high enough to kill many of the more mature trees. (National Interagency Fire Center)
This forest is thickly overgrown and has an unnaturally high amount of biomass, or fuel. A low-intensity fire here would likely grow into a crown fire, killing almost all of these trees. (National Interagency Fire Center)