Six volunteer firefighters use machetes to cut a path through the vines and underbrush of the Chiquitano forest in Bolivia's eastern lowlands. They're approaching the leading edge of a fire that's been burning for hours.

They attempt to smother it with shovelfuls of dirt and water they carry on their backs in tanks normally used to fumigate crops. But the smoke is getting thicker, the heat stronger and swirling winds push the flames forward. Realizing they are overmatched, José Zapata, the only trained firefighter among the group, orders his men to pull out.

"The fire was coming from many sides," Zapata explains as he leads a hasty retreat to the relative safety of a nearby road. "We could have gotten trapped."

Bolivian firefighters, army troops and volunteers have been working nonstop for the past two months amid some of the worst fires in the country's recent history. President Evo Morales, who is running for reelection next month, has suspended his campaign to deal with the expanding disaster.

On Saturday, regional officials estimated nearly 6 million acres of forest and savanna have been torched since August. Eduardo Forno, who heads the Bolivian chapter of Conservation International, says that is almost equal to the area burned this year in the Amazon rainforest in neighboring Brazil, a country eight times larger.