EEL FIRE MANAGEMENT MANUAL -- Prepared by The Nature Conservancy
  
 
TABLE OF CONTENTS
  
 
GENERAL FIRE EFFECTS
 
     
 

2. Fire regulates dry-matter accumulation by:

  • Consuming the humus layer, litter, and sometimes duff
    Eliminating competition for moisture, nutrients, heat, and light
  • Leaving behind dead organic material

3. Fire controls plant activity by:
  • Usually increasing overall native plant productivity
    Usually reducing overall exotic plant productivity
    Triggering release of seeds
  • Sanitizing plants against pathogens such as brownspot on longleaf pine

4. Fire determines wildlife habitat patterns and populations by:
  • Usually increasing the amount, availability, and palatability of foods for herbivores
    Regulating yields of nut and berry-producing plants
    Regulating insect populations which are important food sources for birds
  • Altering the physical structure of wildlife habitat

As described in the Glossary of Wildland Fire Management Terms Used in the United States (McPherson et al., 1990), fire intensity is a measure of the amount of heat energy that is released from a specified length or area of fire throughout a specified time.  It is measured in Btu per square foot or seconds per foot of fire front or kilowatts per meter.  It is the product of three variables: the heat of combustion, the quantity of fuel consumed per unit area in the fire front, and the rate of spread.  Fire severity on the other hand is the degree to which an area has been altered or disrupted by fire.  It is the product of fire intensity and residence time (the amount of time it takes for the front of a fire to cross a specific point).

When speaking of a particular fire, the rating of fire intensity may be different from that of fire severity.  For example, in a grassy community, the fine fuels are very flammable and may produce high flame lengths and a large amount of heat.  The fire intensity may be high but since the fine fuels are consumed quickly and completely, fire does not remain on the ground for very long.  This reduces the fire severity.  On the other hand, in a forested community where there is a deep layer of organic material but not as much litter, fire would burn slowly through the organic material and maybe through the roots of trees.  This type of fire would not produce any large flame lengths or put out any significant heat.  Therefore the intensity would be low but with a disruption in the organic layer, the severity would be high.

The definitions of and differences between fire intensity and fire severity are significant enough to be stated here since they are terms quite often used by fire managers.  A fire manager will be better prepared to write fire management goals and to communicate them to the rest of the fire team with an understanding of intensity and severity.  Also, a fire manager is better able to develop suppression tactics the more familiar they are with fire behavior in particular communities.   		  
     
 
General Fire Effects & Management Considerations

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