A low-severity fire is characterized by minimal, short-term ecosystem effects. Soils are not heated, and overstory vegetation is rarely affected. The result of a low-severity fire is fuel reduction and topkill of understory vegetation. In dry forests that historically burned with a low-severity fire regime, most of the trees have thick bark that prevents damage to the bole. The shrubs and herbs are adapted to burning and either sprout from the root collar or rhizomes or have refractive seed that is stimulated to germinate by the heat of the fire. See Agee 1993, Agee 1998, Debano and others 1998, and Walstad and others 1990 for further discussion.