Canopy Fuels

Canopy fuels are the crowns of trees that form the overstory. The receptivity of the canopy fuels to crown fire is based primarily on three factors: canopy base height, canopy bulk density, and, to a lesser degree, foliar moisture content (Fieldhouse and Dickinson 2003). Canopy base height relates the bottom of the overstory tree crowns to the top of the understory fuel bed and ladder fuels. Canopy bulk density is a measure of the amount of fuel contained in a unit volume of the canopy. High bulk densities present large fuel loads for a fire.

Canopy or crown fuels are typically not consumed during fires in the southeastern US except in isolated cases of "torching" which affect individual trees. Crown foliage is commonly scorched, but rarely is it consumed (i.e., combusted) in crown fires. Particular exceptions are the stand-replacing fires common in sand pine scrub forests in central Florida, in stand-replacing fires in non-indigenous melaleuca forests in south Florida, and limitedly in Table mountain pine forests in the southern Appalachians. General exceptions to this statement occur in fires, either prescribed or wildfire, with extreme fire behavior (caused by low moisture levels, erratic winds, or high fuel loadings).