Photo of the Day 1 March 2008

Bison Herd, Yellowstone National Park, Wyoming, 1996
Photograph by Raymond Gehman
Bison thrive in Wyoming's Yellowstone National Park years after fires swept through more than a third of the park. Ecologists now regard wildfires as natural and beneficial in forest ecosystems. They return nutrients to the soil by burning dead or decaying matter, burn off disease-ridden plants and insects, and clear thick canopies and undergrowth, allowing a new generation of seedlings to grow.