n. A complex process in which fuel is heated, ignites, and burns.
The combustion of plant material begins with heating of the material, which results in conversion of solid or liquid hydrocarbons to gases. As the surface is further heated, the gases emitting from and surrounding the surface are ignited and contribute to further heating of the surface, which in turn leads to oxidation of the solid carbon-based materials remaining on the surface of the material. As the solid surface is oxidized in the combustion process, it recedes and burns further into the particle, eventually consuming it.
The process continues if the energy transferred to the solid surface is equal to or greater than that leaving the particle. The products of the combustion process are primarily CO, CO2, water, ash, and heat. Other trace amounts of various gases and soot particles are also produced. See Tillman and others (1982) for further discussion.