Crown kill height
n. The maximum vertical height at which crown buds are killed.
Below crown kill height, all buds are dead; above it, they are alive. Needles may or may not be scorched above crown kill height.
Crown kill height is the maximum height, measured vertically, from the base of the tree bole to the height within the tree crown above which buds have the survived the fire. For most tree species, crown kill height is equal to crown scorch height. However, the difference can be substantial for trees with large buds or protective structures around the buds (Wagener 1961; Dieterich 1979; Ryan and Reinhardt 1988), such as ponderosa pine, longleaf pine, Jeffery pine, and western larch. Harrington (1987) and Wagener (1961) reported that ponderosa pine with little cambium damage could survive up to 90 percent crown scorch if crown kill was less than 50 percent. Portions of the crown that are scorched but that have live buds are capable of recovering. Current fire behavior models are not able to predict differences between crown kill height and crown scorch height.