The relative behavior of surface-crown fire spread rate modeling systems used in three fire management applications -- CFIS (Crown Fire Initiation and Spread), FlamMap and NEXUS -- is compared using fire environment characteristics derived from a dataset of destructively measured canopy fuel and associated stand characteristics. Although the surface-crown modeling systems predict the same basic fire behavior characteristics (type of fire, spread rate) using the same basic fire environment characteristics, their results differ considerably. Across the range of inputs used in these comparisons, CFIS predicted the highest incidence of crown fire and the highest resulting spread rates, whereas FlamMap predicted the lowest crown fire incidence and lowest spread rates. NEXUS predictions fell between those two systems.