Chapter 2

Question 1

Define fire environment and behavior

Answer 1

Environment: conditions that determine the behavior of a fire. Based on fuel, weather, topography.

Behavior: manner which fuel ignites, flames develop, and fire spreads. Includes other fire phenomena determined by fuel/weather/topography.

Question 2

Relative humidity

Answer 2

(RH%): moisture in the air relative to the total amount of moisture air can hold at a given temperature. Higher temperatures can hold more moisture.

Question 3

Atmosphere stability

Answer 3

Measured by vertical movement of air. Unstable atmosphere incl vertically developed clouds > precursor for storms. Stable resists vertical movement and may reduce or suppress fire.

Question 4

Orographic lift

Answer 4

Movement of storm over mountain ranges. Relative humidity reaches precipitation followed by rain shadow effect on leeward side.

Question 5

Fuel moisture content

Answer 5

Amount of moisture in fuel represented by (wet weight-dry weight)/dry*100

Question 6

Foliar moisture content

Answer 6

Moisture content of live foliage in canopy. Follows seasonal pattern depicted by dip in spring moisture content from new growth

Question 7

Equilibrium moisture content

Answer 7

Occurs when there is no net gain or loss of moisture between fuels and surrounding air

Question 8

Time lag to equilibrium

Answer 8

Describes responsiveness of fuels. Effected by %RH and C = time lag varies

Question 9

Five stable fuel properties

Answer 9

Shape/size, load, compaction, distribution/continuity, position/arrangement

Question 10

Six fuel strata

Answer 10

Subsurface, ground, surface, ladder, aerial, crown

Question 11

Six topographic properties that influence fire behavior

Answer 11

Terrain, slope, aspect, elevation/slope, topographic features, barriers to spread

Question 12

Time and space associated with fire triangle, fire behavior triangle, and fire regime triangle

Answer 12

Generally, time moves from seconds/minutes > hours/weeks/days > decades/centuries. Space moves from a microsite > local > landscape > region.

Question 13

How does surface-area to volume ratio of the fuels affects fire behavior?

Answer 13

Influences rate a fire spreads. Fuels with a higher surface area to volume ratio, such as fine fuels, burn faster than heavy fuels.

Question 14

How does aspect affect fuels, fuel moisture and potential fire behavior?

Answer 14

Determines amount of solar radiation received, fuel load potential, and fuel load moisture

Question 15

What happens to fire behavior when a cold front passes over an active fire?

Answer 15

Creates unstable atmospheric conditions which are favorable for burning environment.