A qualitative measure of the immediate effects of fire on the ecosystem. It relates to the extent of mortality and survival of plant and animal life both aboveground and belowground and to loss of organic matter. It is determined by heat released aboveground and belowground (Paysen et al., 2000). The effect of fire on plants (SKCMP). It is dependant on intensity and residence dependant of the burn. For trees, severity is often measured as percentage of basal area removed. An intense fire may not necessarily be severe.