Module 16: Wildfire and Your Woodland

Module 16 - Glossary

Aspect -- The direction a slope is facing; its exposure in relation to the sun (e.g., north, east, south, west).

Back tank -- A portable water container equipped with a hand pump and backpack straps carried on the back of firefighters.

Burning Period -- That part of each 24-hour day when fires are generally the most active. Usually this is from mid-morning to sundown.

Combustion -- A chemical process in which heat is produced. In the case of wildfires, living and dead fuels are converted to mainly carbon dioxide and water vapour, and heat energy is released very rapidly.

Crown fire -- A fie that advances through the crown fuel layer of a forest, usually in conjunction with a surface fie. See surface fire.

Duff -- The layer of partially and fully decomposed organic matter lying below the litter and immediately above the mineral soil.

Fine fuels -- Fuels that ignite readily and are consumed rapidly by fie (e.g., leaves, needles, twigs, grass).

Fire Behaviour -- The manner in which fuel ignites, flame develops, and fie spreads.

Fire Behaviour Triangle -- A diagram in which the three sides of a triangle represent the three interacting components of fie weather, fuels, and topography.

Fire ecology -- The study of the relationships between fie, the physical environment, and living organisms.

Fire management -- The activities concerned with the protection of people, property, and forest areas from wildfire. Successful fie management depends on effective fie prevention, detection and suppression, and consideration of fie ecology relationships.

Fire prevention -- Activities directed at reducing fie occurrence; includes public education, law enforcement, personal contact, and reduction of fie hazards and risks.

Fire pump -- An engine-driven pump, usually gasoline powered, specifically designed for use in fire suppression.

Fire season -- The period(s) of the year during which fires are likely to start, spread, and damage property. See peak burn.

Fire triangle -- A diagram in which the three sides of a triangle represent the three factors necessary for combustion and flame production: oxygen, heat, and fuel. When any one of these factors is removed, flame production is not possible or ceases.

Fire Weather Index system -- A system of rating fie danger, consisting of six components: Fine Fuel Moisture Code, Duff Moisture Code, Drought Code, Initial Spread Index, Buildup Index, and Fire Weather Index.

Flammability -- The relative ease with which a substance ignites and sustains combustion.

Fuel moisture content -- The amount of water present in fuel, generally expressed as a percentage of the substance’s weight when thoroughly dried.

Green up -- The time during the first half of the season during which hardwood trees and understory vegetation have completed their flushing of new growth. This typically takes place in late spring/early summer.

Hot spot -- A small area of smouldering combustion that may be exhibiting smoke.

Ignition -- The beginning of flame production or smouldering as a fie starts.

Ladder fuels -- Fuels that provide vertical continuity and contribute to the development of crown fires. They can include tall shrubs, small trees, flakes of bark, and tree lichens.

Litter -- The uppermost part of the forest floor consisting of fresh or decomposed organic materials. A component of the duff layer.

Mineral soil -- That portion of the soil layers immediately below the litter and duff. Contains very little combustible material.

Peak burn -- The time of day when fie behaviour is at its most destructive, usually between 10 am and 5 pm during fire season.

Prescribed burning -- The knowledgeable application of fie to a specific land area to accomplish forest management or other objectives.

Pulaski -- A combination chopping and trenching tool, which combines a single-bitted axe blade with a narrow trenching blade fitted to a straight handle. Useful for grubbing or trenching in duff and root mats.

Slash -- Debris left as a result of vegetation being altered by forestry practices and other land use activities. Includes material such as logs, chips, treetops, and branches and uprooted stumps.

Spot fire -- A fie ignited by airborne embers that are carried outside the main fie perimeter. This is usually a small fie that requires little time or effort to extinguish.

Surface fire -- A wildfire that has limited vertical influence and is constrained to the herbs, shrubs, and organic layer on or near the forest floor.

Surface fuels -- All combustible materials lying above the duff layer of the soil. They can include litter, ground vegetation, shrubs, tree seedlings, stumps, and coarse woody debris.

Wildfire -- An unplanned or unwanted natural or human-caused fie.