Predicted and Observed Rates of Spread of Crown Fires in Immature Jack Pine

Abstract

Rates of spread of crown fires predicted by a model are compared to spread rates observed in a series of nine experimental wind-aided crown fires in immature Jack Pine. Selection of two modeling parameters that describe the intensity of radiation issuing from the burning zone within and beneath the live crown layer and from the free flame above the trees is constrained to achieve prediction of the observed spread rate of one fire of the nine documented. Using representative pairs of these parameters, the model predicts the observed rates with rms errors of 0.034-0.037 m/s and maximum absolute error ˜0.06 m/s. Observed spread rates ranged from 0.179 to 0.455 m/s. Prospects for closure of an a priori predictive model for the spread of crown fires are discussed in the light of these results.