Fire As A Physical Factor in Wildland Management

WE usE FIRE to accomplish many goals. Most of our use is based on long years of experience-experience that enables us to predict the results we should obtain from the "feel" of the situation. Research is being conducted, to assist less experienced land managers to understand fire more completely and to provide means for them to predict its effects in given situations. We must better learn to understand and predict all the effects of fire if we are to use fire effectively, or, for that matter, to use fire at all. Recent pressures by various organizations and individuals are directed at air pollution caused by fire. Unless we can effectively demonstrate the reasons we need to use fire as well as its effects on the atmosphere we will find more laws enacted against use of fire. The purpose of this paper is to present a mental model of some physical aspects of fire. Perhaps these can be of u~e in planning some prescribed fires as well as understanding some effects observed in others. Each fire and therefore its effects are the products of many factors. The basic fuel material, quantity, fuel bed geometry, and moisture content are of elementary importance. Compounding the