n. The conveyance of thermal energy resulting from a temperature difference.
Any time a temperature difference occurs within or between objects in thermal contact, thermal energy will transit from the hotter region to the colder region by means of conduction, convection, and/or radiation. Convection and radiation occur at the surface of an object, whereas conduction occurs within an object or between two objects in physical contact.
Related to wildland fire, radiation and convection transfer energy from flames to the surface of adjacent fuel. The heat absorbed at the surface conducts into the fuel mass. Thus, the greater the surface-area-to-volume ratio of the fuelbed, the more a mass can be heated for a given radiation and convection exposure.