Deck 12: Fire

Question 1

Firefighters spray water on a fire to _________________.

A) drown it by cutting off the oxygen supply
B) disrupt the chemical balance of carbon,hydrogen and oxygen needed combustion
C) coat the unburned vegetation and block oxygen from contacting it
D) reduce heat

Answer 1

D

Question 2

During the process of pyrolysis,cellulose in wood breaks apart and yields __________________.

A) flammable hydrocarbon vapours
B) water vapour
C) tar
D) mineral residues
E) all of these are correct

Answer 2

E

Question 3

The organic debris left on the ground after logging or windstorms is called _______________.

A) trash
B) junk
C) gunk
D) brush
E) slash

Answer 3

E

Question 4

Australia's eucalyptus forests are ____________.

A) naturally resistant to fires
B) fire adapted and fire maintained
C) warm and moist so decomposition recycles plant material not wildfires
D) Mediterranean-climate shrublands that provide little fuel for a significant fire event

Question 5

In the photosynthesis reaction in plants,________ is given off as a by-product of the reaction.

A) hydrogen
B) nitrogen
C) carbon dioxide
D) oxygen
E) water

Question 6

Wildfires that race through the treetops are known as ___________________.

A) crown fires
B) bough fires
C) slash fires
D) canopy fires

Question 7

Fire-dependent natural ecosystems include all but which of the following?

A) Grasslands
B) Seasonal tropical forests
C) Some temperate-climate forests
D) The Mediterranean-climate shrublands
E) Tropical rain forest

Question 8

Which of the following is not one of the three stages of combustion?

A) Spark ignition
B) Preheating
C) Flaming combustion
D) Glowing combustion

Question 9

In Mediterranean climates frequent wildfire is necessary for the health of natural plant communities for a number of reasons,which of the following statements is false?

A) Many of the plant species must have the smoke and/or heat of fire to germinate their seeds.
B) Fire helps to control parasites.
C) Fire influences insect behaviour.
D) None of these because wildfire is not necessary to maintain a healthy Mediterranean-type ecosystems.

Question 10

In Canada,lightning-caused wildfires ___________________.

A) are more frequent than people-caused wildfires
B) are typically detected quickly
C) burn a larger area per year than people-caused wildfires
D) occur in clusters near transportation corridors

Question 11

Heat flows outward from a fire by ______________________.

A) diffusion of particles from hotter to cooler areas
B) radiation from flames and hot surfaces
C) convection of hot,lightweight buoyant gases that rise
D) all of these are correct

Question 12

Pyrolysis of cellulose produces which of the following?

A) Methanol (wood alcohol)vapour
B) Water vapour
C) Both water vapour and methanol
D) Chlorophyll
E) Coal

Question 13

A backfire is ________________.

A) a fire initiated in mountainous areas and propagating downslope
B) a fire set intentionally in order to slow an approaching fire by eliminating its fuel supply
C) burned grassland slowly regenerating
D) the incandescent area immediately behind an advancing fire

Question 14

Air tankers drop fire retardant fluids in front of a fire to _________________.

A) coat the unburned vegetation and block oxygen from contacting it
B) disrupt the chemical reactions involved in fire
C) ignite a backfire
D) reduce heat

Question 15

Pyrolysis results in release of all but which of the following?

A) Flammable hydrocarbon vapours
B) Tar
C) Water vapour
D) Oxygen

Question 16

Wet wood is difficult to burn because ______________________.

A) the water in wet wood has a high capacity to absorb heat
B) its temperature must be raised considerably
C) the water displaces oxygen (necessary for ignition)in pores in the wood
D) all of these are correct.
E) the water in wet wood has a high capacity to absorb heat and its temperature must be raised considerably.

Question 17

The term "ladder fuels" refers to _____________________.

A) an evolutionary hierarchy of flammable plants,from primitive ferns to complex flowering trees
B) a hierarchy of carbon-rich flammable materials,from wood to peat,coal,and petroleum products
C) vegetation of varying heights,which allow fire to quickly climb upward
D) fuel made of old woodworking scraps and workbenches

Question 18

Wildfires that advance as a wall of fire do so along a ___________________.

A) smouldering combustion front
B) glowing combustion trap
C) flaming combustion front
D) flaming combustion trap

Question 19

The fire triangle features all but which of the following components?

A) Fuel
B) Heat
C) Oxygen
D) Ignition

Question 20

In effect,the solar energy stored by plants during their growth is ___________________.

A) returned to the atmosphere during fire
B) lost forever during fire
C) used to produce ozone during fire
D) returned to their roots during fire
E) negligibly small

Question 21

Heat-expanded air ___________________.

A) is more dense than cool air because molecules are pushing harder on each other
B) is less dense than cool air
C) has the same density as cool air because matter is neither created nor destroyed in fire
D) contains less energy than cooler air because there are fewer molecules per unit volume

Question 22

Design mistakes,which increase your house vulnerability to fire,include _________________.

A) locating your house on a slope
B) constructing your house of wood
C) having a roof made of flammable wood shingles
D) allowing tree limbs to hang over the roof
E) all of these are correct

Question 23

Catastrophic firestorms are __________________________.

A) wind-driven fires
B) fuel-driven fires
C) driven by upper atmospheric flows of high pressure
D) driven by an advancing thunderstorm front

Question 24

The Canadian Forest Fire Danger Rating System (CFFDRS)uses six codes and indices based on daily observations of rainfall,temperature,relative humidity,and wind speed.Match the temperature,relative humidity and rain with the appropriate fire code.

A) Fine Fuel Moisture Code
B) Duff Moisture Code
C) Drought Code
D) Initial Spread Index

Question 25

What do you call the layer of moss and decomposing organic matter at the base of trees in the boreal forest?

A) Ash
B) Duff
C) Topsoil
D) Slash

Question 26

Factors contributing to the devastating 2003 fire season in British Columbia included all but which of the following?

A) Arson
B) Fuel buildup resulting from several decades of fire suppression
C) Lack of adequate funds and trained personnel
D) Prolonged dry and hot weather

Question 27

What do you call the simple measure of fire danger used to raise public awareness?

A) The Canadian Forest Fire-Danger Rating System (CFFDRS)
B) The Fine Fuel Moisture Code (FFMC)
C) The Fire Weather Index (FWI)
D) The fire triangle
E) The humidex

Question 28

A fire whirl is ___________________.

A) a spinning column of ascending hot air rising from a wildfire and carrying smoke,debris and flame
B) a type of tornado triggered by lightning
C) a warm,dry wind blowing in front of an advancing wildfire
D) a wind strong enough to extinguish a wildfire

Question 29

Wildland Urban Interface (WUI)areas are particularly vulnerable to wildfires because ____________________.

A) fire-fighters have difficulty reaching them
B) jurisdiction issues complicate the response efforts
C) of the close proximity of forest and infrastructure
D) the vegetation in this ecosystem is highly flammable

Question 30

Fire burns faster __________________.

A) on flat ground
B) down a slope
C) up a slope
D) rate of burn is not dependent on amount or direction of slope

Question 31

Match the action for the fire suppression in Figure 12.33 with the appropriate level of fire intensity (kW/m).

A) 0 - 10
B) 2000 - 4000
C) 500 - 2000
D) 4000 - 10 000
E) >30 000

Question 32

Fires with an intensity between 2000 and 4000 kW/m ______.

A) can be suppressed by firefighters using axes and shovels.
B) call for hoses spraying water under pressure.
C) are ferocious,so that the best option is to wait for better weather conditions.
D) are benign and there is no need for any action.
E) None of these answers are correct.

Question 33

Forest fire intensity is ranked according to _____.

A) the wind speed in metres per second.
B) the Duff Moisture Index.
C) the amount of heat energy released per second for a metre of fire front.

Question 34

Some studies suggest that increased burning of Canada's northern boreal forest may lead to ________.

A) more carbon sequestration.
B) more CO₂ released,which in turn may lead to a cooling effect.
C) more cooling as more Sun will be reflected by the snow during the winter months.
D) more cooling as the greenhouse gases build up in the atmosphere.

Question 35

The most intense high heat fires occur in __________________________.

A) forests with trees containing high contents of natural oils
B) grasslands with grasses that have broad,exposed surfaces
C) forests with sparse organic litter
D) grasslands with shrubs that have broad leaves

Question 36

In the boreal forest lightning fires _____________.

A) are usually ignited in the tree crown
B) are usually ignited in the conifer tree stem and branches
C) are usually ignited in the duff layer
D) all of these are correct

Question 37

Fire occurrence and fire-behavior processes is(are)influenced by _______________.

A) fuel
B) weather and topography
C) fuel and people
D) the impact of extraterrestrial debris
E) all of these except the impact of extraterrestrial debris

Question 38

In Mediterranean climates such as California and Australia,the wet winters are too cold and the warm summers too dry ___________.

A) for rotting dead biomass,so wildfire must be less frequent
B) for rotting dead biomass,so wildfire must be more frequent
C) thus the health of plant communities depends on wildfires
D)so wildfires are very rare.

Question 39

Figure 12.25 shows ____________.

A) the early stage of torching
B) an established convection column
C) the fire shortly after ignition
D) a crown fire
E) a tall convection column

Question 40

During a forest fire trees are damaged by heat transfer that occurs by all but which of the following?

A) Conduction
B) Refusion
C) Radiation
D) Convection

Question 41

The energy release in a fire strongly depends on the volume of material consumed,but not on the chemical composition of the plants and organic debris.

Question 42

Fire is the photosynthesis reaction in reverse.

Question 43

The 1916 Cochrane and Matheson fire destroyed 344,000 ha of forest but,fortunately,no lives were lost in this remote area of northeastern Ontario.

Question 44

Eucalyptus trees and shrubs have porous wood and a water content,which results in slow ignition and low heat combustion.

Question 45

Winds blow firebrands ahead of the active fire front allowing crown fires to spread easily across small lakes and rivers.

Question 46

In glowing combustion,the wood burns more slowly but at a higher temperature as the fire consumes the solid wood instead of pyrolized gases,as occurs in flaming combustion.

Question 47

The worst bushfires in Australia coincide with El-Nino events.

Question 48

In Canada,people-caused wildfires are usually more difficult to suppress than lightning-caused fires.

Question 49

Fire is the rapid combination of oxygen with carbon,hydrogen,and other elements of organic material in a reaction that produces flame,heat,and light.

Question 50

Flaming combustion is the stage of least energy release in any fire.

Question 51

In Canada,most forest fires are caused by lightning.

Question 52

In Mediterranean climates such as in the California,Australia,and South Africa,frequent wildfire is necessary for the health of natural plant communities.

Question 53

Because of the poor conductance of heat in wood,the interior of a log remains below the combustion point even when the exterior is engulfed in flames.

Question 54

The three critical components of the fire triangle are ignition,fuel and oxygen.

Question 55

Strong winds tend to blow large fires out rather than making them spread.

Question 56

In many natural environments,fire is necessary to recycle nutrients and regenerate plant communities.

Question 57

Fire tornadoes may carry fiery debris and drop it miles away,starting new fires,but their wind speeds do not get high enough to register on the Fujita scale.

Question 58

Weather has a significant influence on fire occurrence and fire behaviour processes.

Question 59

Firestorms are fires powerful enough to generate their own winds.

Question 60

The duff layer in the boreal forest can support either smouldering or flaming combustion depending on its moisture content.
TRUE

Question 61

Since in recent decades both temperature and forest-fire activity have been rising in some parts of Canada,there is a very well established relationship between climate change and fire activity.

Question 62

Several climate-change studies predict that forest-fire activity will intensify in the future.

Question 63

In general,the impact of climate change on fire-season severity is expected to be the same in all provinces in Canada.

Question 64

The eucalyptus sap contains unique chemicals which acts as a fire retardant.

Question 65

Recent studies show that the earlier spring snowmelt of the forests of the Northern Rockies (U.S. )has no effect on fire activity.

Question 66

Bombardier 415 aircraft are part of Canadian firefighter's arsenal and are used to drop a mixture of water and foam on forest fires to reduce flame height and intensity.

Question 67

According to current studies,the impact of climate change on fire-season severity in Canada is expected to vary regionally,with some areas experiencing increased activity and others lower activity.

Question 68

Since forest fires in Canada are associated with high social,economic and ecological costs,fire and forest managers want to suppress any fire.

Question 69

For the 1972-1980 period,the percentage of chaparral area burned in the United States and in Mexico was about the same,despite enormous efforts made in the United States to suppress fire.