CBM Fire Behavior & Ecology 2 — Questions and Answers
Question 1: Which component of the fire environment triangle describes dead and live plant material available as fuel?
- Topography
- Weather
- Fuels (Correct answer)
- Oxygen supply
Correct answer: Fuels
Fuels are the combustible organic material (dead and live vegetation) that provide the energy source for fire.
Question 2: The concept of 'fine fuel moisture content' is critical because fine fuels ignite most readily when their moisture content falls below approximately:
- 30%
- 20%
- 12% (Correct answer)
- 5%
Correct answer: 12%
Fine fuels with moisture content below about 12% are highly susceptible to ignition and rapid fire spread.
Question 3: What ecological term describes the increase in plant species diversity that often occurs in the first few years following a prescribed burn?
- Climax succession
- Post-fire pulse (Correct answer)
- Pyrodiversity
- Competitive exclusion
Correct answer: Post-fire pulse
A post-fire pulse refers to the temporary spike in plant diversity and productivity as dormant seeds germinate and suppressed species rebound after fire removes competition.
Question 4: In fire behavior, 'spotting' refers to which phenomenon?
- Identifying ignition points on a map
- Embers carried ahead of the fire front to start new ignitions (Correct answer)
- Patchy burn patterns within a fire perimeter
- Flame length measurement at specific intervals
Correct answer: Embers carried ahead of the fire front to start new ignitions
Spotting occurs when firebrands (burning embers) are lofted by convection or wind and land beyond the fire perimeter, starting new fires.
Question 5: The 'critical fire weather' condition known as the Haines Index primarily measures:
- Surface wind speed and direction
- Lower atmosphere stability and dryness contributing to erratic fire behavior (Correct answer)
- Relative humidity at ground level
- Fuel moisture of 1-hour timelag fuels
Correct answer: Lower atmosphere stability and dryness contributing to erratic fire behavior
The Haines Index combines atmospheric stability and moisture deficit in the lower atmosphere to indicate potential for large or erratic fire behavior.
Question 6: Which type of fire spread is generally the slowest and most controllable, making it preferred for prescribed burns on flat terrain?
- Head fire
- Flank fire
- Back fire (backing fire) (Correct answer)
- Spotting fire
Correct answer: Back fire (backing fire)
A backing fire spreads against the wind or downslope, resulting in lower flame lengths, slower rate of spread, and more complete combustion.
Question 7: Fire-adapted ecosystems like longleaf pine savannas evolved with frequent fire primarily because of:
- Soil nutrient depletion requiring ash input
- Lightning-caused ignitions and indigenous burning over thousands of years (Correct answer)
- Invasive species competition requiring fire suppression removal
- Annual flooding events that deposited fire-prone organic matter
Correct answer: Lightning-caused ignitions and indigenous burning over thousands of years
Longleaf pine savannas evolved under a frequent fire regime driven by lightning strikes and intentional burning by Native Americans over millennia.
CBM Fire Behavior & Ecology 2
Which component of the fire environment triangle describes dead and live plant material available as fuel?