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Fires in Nature (Workbook 6) (Wildfires in Victoria, Australia, Feb 2009…
Fires in Nature (Workbook 6)
occurs when oxygen combines with carbon, hydrogen and other organic material producing flame, heat and light
types of fires
crown fires- pass from one tree top to another, extremely high temperatures, strong winds create running crown
surface fire- wall of fire along a combustion front or flaming combustion, burn in grass, shrubs and debris, quick to cool and easy to control
ground fires- moving slowly at ground level through what is known as glowing combustion, slow in humus and peat
10% of wildfires occur naturally
lightening strikes
molten lava
80-90% are triggered by people
burning out of control
falling power lines
camp fires
cigarettes
arson
Ignition
cause of the fire
increased levels of tourism have increased fires
increased suburbanisation
more space between houses so more vegetation (USA)
Fuel
plants or vegetation form the main source of fuel
large quantity and dry
Factors
presence of vegetation
dry climate but wet enough for vegetation to grow (semi-arid)
recent dry weather
high wind speeds to advance the fire
steep topography as rising heat dries out vegetation
Impacts
social
people may become trapped and killed by wildfires
timber can be burned- industry provides jobs and income
people's property and homes can be destroyed
burned areas are ugly and aesthetically displeasing
people may have to evacuate
visibility will be reduced by smoke and can cause accidents
air quality may be affected, with smoke causing respiratory problems
Economic
infrastructure can be damages and needs to be replaced
wildfires are very expensive for emergency services to tackle
Environmental
crops and livestock may be damaged meaning agriculture is affected
with vegetation burnt, less interception may increase the flood risk
ashes from fire may ultimately add fertility to the soil
fire may kill or injure vegetation
some fires may benefit the ecosystem by clearing vegetation
larger species may be driven from an area
soil may be damaged if organic matter is burned
after a fire, a more diverse range of species may develop
fire may kill off pests that would have attacked native vegetation
alien species may be destroyed
smaller species may not be able to flee so may be killed
water quality may be badly affected by run-off of burnt particles
Political
evacuated people seek temporary shelter
communities may be split up if people move away following a fire
Responses
1) MITIGATION
controlled burning to get rid of litter
firebreaks
gaps between houses
land use planning
2) PREPAREDNESS
computer simulations of fires to predict behaviour
education
warning systems
community action
insurance
4) ADAPTATION
fire- resistant materials
chimneys have spark resistant fitted
3) RESPONSE
spraying water and chemicals
bulldozing breaks in vegetation
retardants sprayed onto fire
replanting trees
Wildfires in Victoria, Australia, Feb 2009
Black Saturday
400 bushfires
temp regularly above 40 degrees
NW winds of over 100km/h
10% low humidity
covered in Eucalyptus forests which have oil-rich foliage
caused by lightening strikes, sparks from fallen power lines, sparks from power tools and machinery, arson
social
173 deaths including 1 firefighter
440 hospitalised
3,500 properties destroyed
7,000 displaced
loss of electricity distrupted over 60,000
economic
businesses that relied on crops and livestock suffered
environmental
loss of 12,000 livestock including sheep, cattle and horses
large national parks destroyed
1 million animals died according to RSPCA
ash and smoke into atmosphere- increase Co2
SHORT TERM
State Health Emergency Response Plan
Stay and Defend or Leave Early Policy
Replacing power lines
LONG TERM
not living in bushlands
clearing trees
fire retardant materials
building regulations
government came under criticisms for allowing housing in Marysville to be rebuilt as 90% had been destroyed