‘Fuels’ is a term coined by fire scientists to reference anything flammable. Fuels make wildfires grow hotter and faster. A general fuels reduction plan manages ground fuels and ladder fuels throughout a forest, ‘ladder fuels’ being flammable objects that take a ground fire up into the canopy (normally small trees under larger trees, or the limbs of larger trees).
Shaded Fuel Breaks remove ground and ladder fuels, leaving trees whose crowns are spaced ten to twenty feet apart, or clumps of trees whose crowns are separated twenty to forty feet from the crowns of other clumps. A Fire Line eliminates all above-ground fuels in a certain area.