Wildfires were once essential to the American West. Prairies and forests burned regularly, and those fires not only determined the mix of flora and fauna that made up the ecosystem, but they regenerated the land.
When people replaced wilderness with homes and ranches, they aggressively eliminated fire. But now, scientists are trying to bring fire back to the wilderness, to recreate what nature once did on its own.
One place they're doing this is Centennial Valley, in southwestern Montana.
The deaths of 19 firefighters near Yarnell, Ariz., this summer have focused a lot of attention on just how bad wildfire has become in the West. And research predicts the situation is going to get worse.
Over the past decade, the region has seen some of the worst fire seasons on record. In addition to lives lost, the fires have cost billions in terms of lost property and in taxpayer money spent fighting the blazes.