Fire managers are gathering this week in Flagstaff for a first-of-its-kind training in prescribed burns. Officials say the Prescribed Fire Training Exchange, or TREX, is a unique opportunity for fire personnel across the country to learn about prescribed fire, smoke management and wildland-urban interface. Fire managers from nine different agencies will be involved, including the Flagstaff Fire Department and the Summit Fire and Medical District. TREX managers will coordinate with neighboring national forest, parks, fire departments and the Arizona Department of Environmental Quality to monitor the smoke impacts of prescribed burns. Several are planned in the coming weeks for the greater Flagstaff area, including Observatory Mesa, the U.S. Naval Observatory and Rogers Lake area.