Aperiodic instability of the front of a crown forest fire

The stability of the three-zone structure of the front of a crown forest fire, which includes zones of vaporization, pyrolysis, and combustion gaseous products, is analyzed by the method of small perturbations. This model more accurately describes the physics of the actual process of propagation of upper forest fires. A characteristic equation is obtained and an analysis of its roots yields neutral curves for analysis of the monotonic instability of the fire front. It is shown that instability of fire-front propagation arises in a certain wavelength range.