Optimum packing ratio
n. Packing ratio corresponding to maximum reaction velocity.
Optimum packing ratio is a term used in the Rothermel's (1972) surface fire spread model indicating the packing ratio that optimizes the reaction velocity term of the spread model. Optimum packing ratio is a function of the fineness of fuel particles, which is measured by the characteristic surface-area-to-volume ratio of the fuelbed. Optimum packing ratio does not optimize fire behavior (rate of spread or fireline intensity).