The high mountain forests of western North America need fire.
Fire returns nutrients to the soil and replaces old stands and
ground debris with young forest. Intense fires are a
characteristic of the conifer forests, though they occur
infrequently—once every 100 to 300 years. The year 1988 brought
one of those infrequent, severe fires to Yellowstone National
Park. Drought and high temperatures combined to create extreme
fire conditions. Fifty wildfires ignited, seven of which grew
into major wildfires. By the end of the year, 793,000 acres had
burned. This false-color image, taken by the Landsat 5 satellite
in 1989, shows the burn scar left on the landscape (orange and
red) by the 1988 inferno. It takes many decades for a conifer
forest to recover to pre-fire conditions, and through the use of
Landsat, researchers have been able to chronicle the recovery
over the past two decades. See the year-to-year images in Earth
Observatory’s World of Change article: Burn Recovery in
Yellowstone. Western conifers burn wh