Arson fire - A fire set on purpose by anyone to burn, or spread to, vegetation or property. 

Backfire - A fire-suppression technique of creating a firebreak by burning all fuel between the existing fire line and the oncoming fire.  It can also be used to change the direction and the force of the fire convection column.

Canopy - The leaves and branches making up the "roof" of the forest.

Combustible material -Any material that can catch on fire and burn.

Combustion - the act of burning.

Control line - Also often called a "fire line," this includes lines constructed by firefighters as well as natural barriers to fire such as rock outcroppings, roads and streams or other water bodies.  Crews construct fire lines by using shovels, pulaskis, rakes, fire plows, harrows and chainsaws to clear the line of vegetation down to the mineral soil so that the fire will have nothing to burn when it gets to that point.

Crown fire - A wildfire that spreads across the tops of trees or shrubs more or less independently of any fire on the ground.

Defensible space - An area, usually a width of 30 feet or more, between a home or other structure and a potential wildfire where the combustibles have been removed or modified.

Drip torch - A small fuel tank with a handle, nozzle and igniter used to drip a burning mixture of oil or diesel and gasoline to ignite a prescribed fire or a backfire.

Ecosystem - A community where living organisms and non-living components of the environment are acting as a unit.  

Environment - The sum of all external conditions affecting the life, development and survival of an organism.

Escape route - A route away from dangerous areas or a fire; should be preplanned.

Fire break - A natural or man-made barrier used to stop fires or keep them from spreading.

Fire exclusion - Total or near total elimination of fire from an ecosystem.

Fire inclusion - The intentional use of prescribed fire to manipulate an ecosystem.

Fire prevention - Activities, including education, enforcement and administration directed at reducing the number of wildfires, the cost of suppression and the cost of related fire damages.

Fire triangle - A learning tool where the sides of a triangle are used to represent the three factors (oxygen, heat, fuel) needed to catch on fire, burn and produce flame; removing any of the three factors causes the fire to go out.

Firefighter - A person trained to suppress structural and/or wildland fire.

Forest - An ecosystem with dense or not-so-dense tree cover, often containing separate stands of trees, and commonly including meadows and streams.

Forest ranger - An employee of the Forestry Commission whose duties include fire prevention and wildland firefighting. 

Fuel break - A wide strip, or block of land where the vegetation has been permanently changed or reduced so that fires burning into it can be put out more easily.

Fuel - All combustible material within the wildland/urban interface or intermix, including vegetation and structures.

Ladder fuels - Fuels (like shrubs and branches) that carry the fire from the ground to the tops of trees, the same way a person would climb a ladder. 

Mop-up - Once a fire is controlled, mop-up begins.  This is the process of making sure all remaining hot spots within the fire's perimeter are completely out.  

Natural barrier - Any area that does not have flammable material (such as a stream) and can help keep wildfires from spreading.  

Overstory - The portion of the trees in a forest that forms the upper or uppermost layer.

Prescribed burning - A forest management tool where fire is applied in a skillful manner to forest fuels, in a definite place, for a specific purpose, under exacting weather conditions, to achieve manageable objectives, such as to improve forage and habitat for wildlife and livestock, to improve watershed, or to reduce hazardous build up of fire fuels.

Smoke - (1) The visible products of combustion rising above fire.  (2) Term used when reporting a fire or probable fire in its initial stages.

Smokey Bear - "Smokey" the fire prevention bear has been our nation's symbol for the prevention of wildfires for over 50 years.  His main message has always been, "Remember . . . only you can prevent wildfires."

Suppression (of fire) - The act, or process of putting a fire out.

Understory - The layer in a forest below the overstory, formed by lower-growing vegetation under the tall trees, like shorter trees or bushes.  

Vegetation - plant life, or total plant cover of an area.

Wildfire - An unwanted or unplanned fire burning in forests or wildland areas that threatens to destroy life, property or natural resources.  

Wildland - Land not used for agriculture (such as: grazing, row crops, commercial forestry), urban development, mining, parks or reserves.

Wildland-Urban Interface - The line, area, or zone where structures and other human development meet or intermingle with undeveloped wildland or vegetative fuels.

Wildlife - All non-domesticated animal life.