FIRE 321 MIDTERM.
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Preheating - Answer: The phase where fuels are heated by nearby flames or radiation,
driving off water and volatile compounds before ignition.
Pyrolysis - Answer: Thermal decomposition of organic material into volatile gases and char
as temperature increases, preceding visible flames.
Gaseous Combustion - Answer: The flaming phase where volatile gases mix with oxygen
and burn, producing light, heat, and flame.
Smoldering Combustion - Answer: Slow, low-temperature oxidation of solid fuels (like duff
or decayed wood) without visible flame; can persist long after flaming stops.
Conduction - Answer: Transfer of heat through direct contact between materials (e.g.,
through soil or plant tissue).
Convection - Answer: Transfer of heat by movement of hot air or gases, often carrying
embers and driving fire spread uphill.
Radiation - Answer: Transfer of heat energy in electromagnetic waves, preheating fuels at a
distance.
Surface Fire - Answer: Burns litter, grasses, and low vegetation near the ground surface.
Ground Fire - Answer: Burns organic matter below the surface (e.g., duff, peat), often
smoldering and hard to detect.
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,Crown Fire - Answer: Burns tree canopies, spreading rapidly through treetops, typically
driven by strong winds and dry fuels.
Fire Intensity - Answer: The rate of heat energy release per unit length of fire front;
measures fire's energy output.
Fire Line Intensity (FLI) - Answer: Energy released per unit length of the fire front per second
(kW/m); quantifies fire behavior at the flame front.
Fire Severity - Answer: The ecological impact of a fire on vegetation and soil, often
measured post-fire.
Flame Length - Answer: The average height of flames above the fuel bed; correlates with
fireline intensity and difficulty of control.
Rate of Spread (ROS) - Answer: The speed at which a fire advances horizontally, typically in
meters or chains per hour.
Heat per Unit Area - Answer: The total heat energy released by combustion per unit area
burned; indicates potential soil heating and vegetation damage.
Ground Fuel - Answer: Organic matter beneath the surface, such as duff and decomposed
roots.
Duff - Answer: Partially decomposed organic material on the forest floor below litter.
Litter - Answer: Freshly fallen leaves, twigs, and debris on the ground.
Surface Fuel - Answer: Grass, shrubs, downed logs, and litter that burn in surface fires.
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, Canopy (Crown) Fuel - Answer: Leaves, branches, and twigs in the forest canopy that
sustain crown fires.
Live Herbaceous Fuel - Answer: Living grasses and forbs that contribute to fire spread when
dry.
Live Woody Fuel - Answer: Living shrubs and small woody plants; contain higher moisture
but may burn under severe conditions.
Fuel Moisture - Answer: The amount of water in fuel, expressed as a percentage of dry
weight; critical for ignition potential.
Time-lag Fuel Classes - Answer: Categories (1-hour, 10-hour, 100-hour, 1000-hour fuels)
describing how quickly fuels gain or lose moisture based on size and exposure.
Fire Regime - Answer: The characteristic pattern of fires in an ecosystem over time
(frequency, size, intensity, seasonality).
Fire Frequency - Answer: How often fires occur in a given area.
Mean Fire Return Interval (MFRI) - Answer: The average time between successive fires at a
given location.
Fire Return Interval Departure (FRID) - Answer: The degree to which current fire intervals
differ from historical norms.
Fire Magnitude/Severity - Answer: Combined measure of fire intensity and its ecological
effects.
APPHIA – Crafted with Care and Precision for Academic Excellence.
3
From question to perfection| Study with confidence!
Preheating - Answer: The phase where fuels are heated by nearby flames or radiation,
driving off water and volatile compounds before ignition.
Pyrolysis - Answer: Thermal decomposition of organic material into volatile gases and char
as temperature increases, preceding visible flames.
Gaseous Combustion - Answer: The flaming phase where volatile gases mix with oxygen
and burn, producing light, heat, and flame.
Smoldering Combustion - Answer: Slow, low-temperature oxidation of solid fuels (like duff
or decayed wood) without visible flame; can persist long after flaming stops.
Conduction - Answer: Transfer of heat through direct contact between materials (e.g.,
through soil or plant tissue).
Convection - Answer: Transfer of heat by movement of hot air or gases, often carrying
embers and driving fire spread uphill.
Radiation - Answer: Transfer of heat energy in electromagnetic waves, preheating fuels at a
distance.
Surface Fire - Answer: Burns litter, grasses, and low vegetation near the ground surface.
Ground Fire - Answer: Burns organic matter below the surface (e.g., duff, peat), often
smoldering and hard to detect.
APPHIA – Crafted with Care and Precision for Academic Excellence.
1
,Crown Fire - Answer: Burns tree canopies, spreading rapidly through treetops, typically
driven by strong winds and dry fuels.
Fire Intensity - Answer: The rate of heat energy release per unit length of fire front;
measures fire's energy output.
Fire Line Intensity (FLI) - Answer: Energy released per unit length of the fire front per second
(kW/m); quantifies fire behavior at the flame front.
Fire Severity - Answer: The ecological impact of a fire on vegetation and soil, often
measured post-fire.
Flame Length - Answer: The average height of flames above the fuel bed; correlates with
fireline intensity and difficulty of control.
Rate of Spread (ROS) - Answer: The speed at which a fire advances horizontally, typically in
meters or chains per hour.
Heat per Unit Area - Answer: The total heat energy released by combustion per unit area
burned; indicates potential soil heating and vegetation damage.
Ground Fuel - Answer: Organic matter beneath the surface, such as duff and decomposed
roots.
Duff - Answer: Partially decomposed organic material on the forest floor below litter.
Litter - Answer: Freshly fallen leaves, twigs, and debris on the ground.
Surface Fuel - Answer: Grass, shrubs, downed logs, and litter that burn in surface fires.
APPHIA – Crafted with Care and Precision for Academic Excellence.
2
, Canopy (Crown) Fuel - Answer: Leaves, branches, and twigs in the forest canopy that
sustain crown fires.
Live Herbaceous Fuel - Answer: Living grasses and forbs that contribute to fire spread when
dry.
Live Woody Fuel - Answer: Living shrubs and small woody plants; contain higher moisture
but may burn under severe conditions.
Fuel Moisture - Answer: The amount of water in fuel, expressed as a percentage of dry
weight; critical for ignition potential.
Time-lag Fuel Classes - Answer: Categories (1-hour, 10-hour, 100-hour, 1000-hour fuels)
describing how quickly fuels gain or lose moisture based on size and exposure.
Fire Regime - Answer: The characteristic pattern of fires in an ecosystem over time
(frequency, size, intensity, seasonality).
Fire Frequency - Answer: How often fires occur in a given area.
Mean Fire Return Interval (MFRI) - Answer: The average time between successive fires at a
given location.
Fire Return Interval Departure (FRID) - Answer: The degree to which current fire intervals
differ from historical norms.
Fire Magnitude/Severity - Answer: Combined measure of fire intensity and its ecological
effects.
APPHIA – Crafted with Care and Precision for Academic Excellence.
3
