Exam 3 Study Guide - Eaps 106
You should know the following from the lectures:
Unit 7 - Wildfires
1. The main characteristic of fire
Exothermic (heat producing), self-perpetuating, chemical reaction initiated by a small amount of
heat.
2. The components of the fire tetrahedron
Fuel, heat energy, oxygen, uninhibited chain reaction
3. The phases of a fire and what happens in each
Preignition - Unburned fuels need to be heated up. Heat causes fuels to begin to give off vapors
that can burn.
Combustion - Fuel vapors combine with oxygen in a chemical reaction that releases more heat
Smoldering - Ash cover leads to slow, low temperature burning and inhibits new fuels from
lighting.Forest Service
4. What surface and crown fires are
Surface fires involve grasses, pine needles, and shrubs. The large surface area to volume ratio
of these fuels allow them to burn more easily and spread more rapidly.
Crown fires are those in which flames reach the top (crown) of trees where fine branches and
needles can burn very rapidly. They are the hottest and fastest moving of all wildfires and
extremely difficult to fight. Can’t fight these, you can lead it or steer it, redirect it, but not fight it.
5. What starts most wildfires in the U.S.?
Human causes - amount of acres burned is greater with lightning, but more fires are caused by
humans
6. Why fires started by lightning tend to burn more acres
Lightning strikes in remote areas, so it’s harder to notice that they got started and often occur in
areas hard to get to by vehicle
7. The factors that influence the potential for a wildfire to spread
Type of vegetation (desert shrub for example), amount of rainfall, average temperature (higher
temps mean drier fuels and larger potential to burn), topography (steep slopes = fires burn
easier uphill because fire aims toward fuel above it)
8. The largest wildfire to occur in United States history
The Great Fire of 1910
9. The original and current policies of the U.S. Forest Service toward fighting wildfires
Original - Fight all fires everywhere
Current - Let them burn in primitive areas unless they endanger people or structures
grasses
, 10. The mascot used by the U.S. Forest Service to promote fighting forest fires
Smokey the Bearextin
11. Why extinguishing smaller wildfires can be a bad practice
Some natural brush fires can help clear the fuel and prevent fuel buildup that could lead to even
larger fires that can be more catastrophic
12. The lesson of The Legend of Coyote in terms of wildfires
“Native people are observers of the minutiae of natural forces, as well as the macro impact, so
the tale winds all of those dualisms together and produces a tale about life coming from death
and destruction…”
13. Why grasses survive fires better than trees and why ancient hunters set fires to grasslands
Because only grasses can regrow from the roots (trees and shrubs cannot). Ancient hunters set
wetting fires to maintain grasslands and prevent trees and shrubs from taking over.
14. How backburns, firelines, wetting, and smothering each help fight wildfires
Backburns - Also starves the fire by burning fuel in advance, preventing it from spreading and/or
growing larger, indirect attack
Firelines - cuts down to soil to starve the fire of fuel, indirect attackhotshot
Wetting - chemically quenching, direct attack when on the fire, indirect when dropped on
unburned fuels. Can be done in front of the fire to prevent them from moving beyond that point.
Many times the fire is too hot to simply quench it entirely. HOTSHOT
Smothering - Direct attack, works to remove oxygen from the fire.
15. The general characteristics uses of Hotshot smokecrews
20-22 firefighters who respond to large, high-priority fires, assigned to the most challenging
tasks. Trained and equipped to work in remote areas for extended periods of time with minimal
logistical support. Usually organized nationally (or state), not typically municipally.
Organized by agencies like the forest service, national park service, etc.olored red
16. Why fire retardants dropped from air tankers colored red
So that you can see where you’ve already dropped
17. What kind of plane first used as an air tanker
Crop duster - SEAT (Single engine air tanker)
18. Where air tankers usually drop their loads
Next to the fire to wet the unburned fuels and prevent the fire from creeping further, sometimes
on a ridge because fire can climb over the ridge
You should know the following from the lectures:
Unit 7 - Wildfires
1. The main characteristic of fire
Exothermic (heat producing), self-perpetuating, chemical reaction initiated by a small amount of
heat.
2. The components of the fire tetrahedron
Fuel, heat energy, oxygen, uninhibited chain reaction
3. The phases of a fire and what happens in each
Preignition - Unburned fuels need to be heated up. Heat causes fuels to begin to give off vapors
that can burn.
Combustion - Fuel vapors combine with oxygen in a chemical reaction that releases more heat
Smoldering - Ash cover leads to slow, low temperature burning and inhibits new fuels from
lighting.Forest Service
4. What surface and crown fires are
Surface fires involve grasses, pine needles, and shrubs. The large surface area to volume ratio
of these fuels allow them to burn more easily and spread more rapidly.
Crown fires are those in which flames reach the top (crown) of trees where fine branches and
needles can burn very rapidly. They are the hottest and fastest moving of all wildfires and
extremely difficult to fight. Can’t fight these, you can lead it or steer it, redirect it, but not fight it.
5. What starts most wildfires in the U.S.?
Human causes - amount of acres burned is greater with lightning, but more fires are caused by
humans
6. Why fires started by lightning tend to burn more acres
Lightning strikes in remote areas, so it’s harder to notice that they got started and often occur in
areas hard to get to by vehicle
7. The factors that influence the potential for a wildfire to spread
Type of vegetation (desert shrub for example), amount of rainfall, average temperature (higher
temps mean drier fuels and larger potential to burn), topography (steep slopes = fires burn
easier uphill because fire aims toward fuel above it)
8. The largest wildfire to occur in United States history
The Great Fire of 1910
9. The original and current policies of the U.S. Forest Service toward fighting wildfires
Original - Fight all fires everywhere
Current - Let them burn in primitive areas unless they endanger people or structures
grasses
, 10. The mascot used by the U.S. Forest Service to promote fighting forest fires
Smokey the Bearextin
11. Why extinguishing smaller wildfires can be a bad practice
Some natural brush fires can help clear the fuel and prevent fuel buildup that could lead to even
larger fires that can be more catastrophic
12. The lesson of The Legend of Coyote in terms of wildfires
“Native people are observers of the minutiae of natural forces, as well as the macro impact, so
the tale winds all of those dualisms together and produces a tale about life coming from death
and destruction…”
13. Why grasses survive fires better than trees and why ancient hunters set fires to grasslands
Because only grasses can regrow from the roots (trees and shrubs cannot). Ancient hunters set
wetting fires to maintain grasslands and prevent trees and shrubs from taking over.
14. How backburns, firelines, wetting, and smothering each help fight wildfires
Backburns - Also starves the fire by burning fuel in advance, preventing it from spreading and/or
growing larger, indirect attack
Firelines - cuts down to soil to starve the fire of fuel, indirect attackhotshot
Wetting - chemically quenching, direct attack when on the fire, indirect when dropped on
unburned fuels. Can be done in front of the fire to prevent them from moving beyond that point.
Many times the fire is too hot to simply quench it entirely. HOTSHOT
Smothering - Direct attack, works to remove oxygen from the fire.
15. The general characteristics uses of Hotshot smokecrews
20-22 firefighters who respond to large, high-priority fires, assigned to the most challenging
tasks. Trained and equipped to work in remote areas for extended periods of time with minimal
logistical support. Usually organized nationally (or state), not typically municipally.
Organized by agencies like the forest service, national park service, etc.olored red
16. Why fire retardants dropped from air tankers colored red
So that you can see where you’ve already dropped
17. What kind of plane first used as an air tanker
Crop duster - SEAT (Single engine air tanker)
18. Where air tankers usually drop their loads
Next to the fire to wet the unburned fuels and prevent the fire from creeping further, sometimes
on a ridge because fire can climb over the ridge
