The effects that concern the direct or immediate consequences of fire, such as biomass consumption, crown scorch, bole damage, and smoke production. First order effects form an important basis for predicting secondary effects such as tree regeneration, plant succession, and changes in site productivity, but these involve interaction with many other non-fire variables. 

North, south, east, west; used for giving directions and information from the ground or air in describing the fire (e.g., the west flank or east flank, not right flank or left flank).

Number of resources used to attack a fire.

Two or more units of any one type working one in front of the other to accomplish a specific fire suppression job; the term can be used in connection with crews of firefighters, power pumps, bulldozers, etc.

The chance that a firebrand will cause an ignition when it lands on receptive fuels.

The display or printout of an infrared scanner operating over a fire.

A heat detection system used for fire detection, mapping, and hotspot identification.

Any uncontrolled fire near to or heading toward an area under organized fire protection.

The boundary of a fire at a given moment.

A radio transmitter attached to the aircraft structure which operates from its own power source on 121.5 MHz and 243 MHz. The transmitter transmits a distinctive downward swept audio tone for homing purposes and is designed to function without human action after an accident.