Facing the worst outbreak of forest fires in three years, cattle ranchers and indigenous tribesmen in the southern Amazon have teamed up to extinguish nearly two dozen blazes over the past three months, offering hope that new alliances between long-time adversaries could help keep deforestation rates in the Brazilian Amazon on a downward trajectory. The voluntary fire brigades, which have now spent more than 400 hours battling fires, are the product of partnership between Aliança da Terra, a Brazilian nonprofit working to improve land stewardship by cattle ranchers in the heart of the Amazon; Kayapó and Xavante Indians; local authorities; and the U.S. Forest Service.