Glossary of Terms

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Dead Fuels:
Fuels with no living tissue in which moisture content is governed almost entirely by atmospheric moisture ( relative humidity and precipitation), dry-bulb temperature, and solar radiation.

Debris Burning:
A fire originally set for the purpose of clearing land or for rubbish, garbage, range, stubble, or meadow burning.

Defensible Space:
An area either natural or manmade where material capable of causing a fire to spread has been treated, cleared, reduced, or changed to act as a barrier between an advancing wildland fire and resources or lives at risk. In practice, defensible space is generally defined as an area of 30 feet or more around a structure that is cleared of flammable brush or vegetation or other fuels.

Deployment:
Removing a fire shelter from its case and using it as protection against fire.

Detection:
The act or system of discovering and locating fires, for example, by staff or volunteers in lookout towers.

Direct Attack:
Any treatment of burning fuels, such as by wetting, smothering, or chemically quenching the fire or by physically separating burning fuels from unburned fuels.

Dispatch:
The implementation of a command decision to move a resource or resources -- such as crews or dozers or engines or aircraft -- from one place to another.

Dispatch Center:
A facility from which resources are directly assigned to an incident.

Dispatcher:
A staff person who receives reports of discovery and status of fires, confirms their locations, receives orders for resources and takes action to provide people and equipment needed for control, and sends them to the designated locations.

Division:
Divisions are used to divide an incident into geographical areas of operation. Divisions are established when the number of resources exceeds the span-of-control of the operations chief. A division is located with the Incident Command System organization between the branch and the task force or strike team.

Dozer:
Any tracked vehicle with a front-mounted blade used for exposing mineral soil or constructing fireline or safety zones.

Dozer Line:
Fireline constructed by a dozer.

Drip Torch:
A hand-held device for igniting fires by dripping flaming liquid fuel onto the materials or area to be burned; consists of a fuel fount, burner arm, and igniter. The fuel used is generally a mixture of diesel and gasoline.

Drop Zone:
Target area for airtankers, helicopters, and cargo dropping.

Drought Index:
A number representing the net effect of evaporation, transpiration, and precipitation in producing cumulative moisture depletion in deep duff or upper soil layers.

Dry Lightning Storm:
Thunderstorm in which negligible precipitation reaches the ground. Also called a dry storm.

Duff:
The layer of decomposing organic materials lying below the litter layer of freshly fallen twigs, needles, and leaves and immediately above the mineral soil.