Fireline is a break in fuel, made by cutting, scraping, or digging with a bulldozer or hand tools.
Suppression U.S. Department of the Interior
What is a fire triangle? - Quora
WF: Fire in Depth - Fire (U.S. National Park Service)
News - Wildland Fire Program (U.S. National Park Service)
What is the advantage of overlapping fields of fire? - Quora
Fire Management - Yellowstone National Park (U.S. National Park Service)
WF: Responding to Fire - Fire (U.S. National Park Service)
Wildland Fire Strategic Plan - Fire (U.S. National Park Service)
National Park Service Fire and Aviation Management