Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Glossary of Terms

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

- B -

A fire set along the inner edge of a fireline to consume the fuels in the path of a wildfire and/or to change the direction of force of the fire's convection column.

Backpack Bucket:
A portable sprayer with a hand pump, fed from a liquid-filled container fitted with straps and worn like a backpack, used mainly in fire and pest control. (See also Bladder Bag)

Bambi Bucket:
A collapsible bucket slung beneath a helicopter. Used to dip water or retardant from a variety of sources for fire suppression.

A system of interactive computer programs for modeling fuels and fire behavior that includes two systems: BURN and FUEL.

Biomass is any organic matter that is available on a renewable or recurring basis, including trees, plants and associated residues; plant fiber; poultry litter and other animal wastes; industrial waste; and the paper component of municipal waste.

Bladder Bag:
A collapsible backpack portable sprayer made of neoprene or high-strength nylon fabric fitted with a pump. (See also Backpack Pump)

Trees that are knocked down during a windthrow. There is controversy about what action should be taken when Blowdown occurs on forested lands, because some people want the blowdown trees to be left on the ground, but when these trees are not removed from the forests many times there is an infestation of beetles and other unwanted insect species that can weaken the surrounding forests.

A sudden increase in fire intensity or rate of spread strong enough to prevent direct control or to upset control plans. Blow-ups are often accompanied by violent convection and may have other characteristics of a fire storm. (See Flare-up.)

A collective term that refers to stands of vegetation dominated by shrubby, woody plants or low-growing trees, usually of a type undesirable for livestock or timber management.

Brush Fire:
A fire burning in vegetation that is predominantly shrubs, brush, and scrub growth.

Bucket Drops:
The dropping of fire retardant or suppressant from a specially designed bucket slung beneath a helicopter.

Buffer Zones:
An area of reduced vegetation that separates wildland areas from vulnerable residential or business developments. This barrier is similar to a greenbelt in that it is often used for another purpose such as agriculture or recreation, or parks or golf courses.

Bump-up Method:
A progressive method of building a fireline on a wildfire without changing firefighters' relative positions in the line. Work is begun with a suitable space between firefighters. Whenever one overtakes another, all crew members ahead move one space forward and resume work on the uncompleted part of the line. The last in line does not move ahead until completing his or her section of line.

Burn Out:
Setting fire inside a control line to widen it or to consume fuels between the edge of the fire and the control line.

Burn Plan:
This document provides the prescribed fire burn boss the information needed to implement an individual prescribed fire project. Also called prescribed fire plan.

Burning Ban:
A declared ban on open-air burning within a specified area, usually put into place by the agency in charge of managing that area and usually in cases of sustained high fire danger.

Burning Conditions:
The state of the combined factors of the environment that affect fire behavior in a specified fuel type.

Burning Index:
An estimate of the potential difficulty of fire containment as it relates to the flame length at the most rapidly spreading portion of a fire's perimeter.

Burning Period:
That part of each 24-hour period when fires spread most rapidly, typically from 10:00 a.m. to sundown.