Fires in Nature Flashcards
What are surface fires?
Fires that sweep rapidly over the ground
What can ground temperatures reach during surface fires?
Over 1000 degrees C
What are crown fires?
Fires that occur and spread through the canopy of trees.
What does the nature of fire depend upon?
Type of plant
Strength of wind
Topography
What does the nature of the fire mainly depend on after the fire has dried out the vegetation?
The wind
What two things are needed for a fire to spread?
An ignition source and fuel
What is the main source of ignition for natural fires?
A lightening strike
What affects the frequency of electrical storms?
Climate
What is another cause of fire?
Human intervention
In which ways do humans start wildfires?
Falling power lines Carelessly discarded cigarettes Children playing with matches Camp fires Agricultural fires (controlled burning) Arson
What had led to an increased danger of wildfires in the USA and Australia?
Tourism
What does the fuel of a fire need to be?
Sufficient quality and dry enough to burn
What does climate affect (aside from frequency of electrical storms)?
The frequency and duration of droughts during which the vegetation and litter has an opportunity to accumulate and dry out.
The type of vegetation that will grow in an area
The rate at which litter will be produced
Do fires tend to be a rural or urban hazard?
Rural
List 3 places that are susceptible to fires?
Southern Europe
Australia
California
Canada
What makes areas more susceptible to fires?
Dry vegetation and lightning strikes
Dry season
Semi-arid climate – susceptible to drought
How can fires affect ecosystems?
They clear vegetation and aid seed germination
Stimulate the growth of certain plants
Rid an area of insects and some parasites
What is the name of species that can withstand fire?
Pyrophytic
How is the baobab tree pyrophytic?
It has resistant bark
Where can the banksia plant be found?
Australia
Why does the banksia plant need fire?
It needs fire to open its woody fruit and therefore regenerate
Why has fire not been a real hazard to tropical rainforests?
Due to the tropical climate
Why have the Amazon Basin and Indonesia experienced wildfires in recent years despite being tropical rainforests?
Forest clearance has gotten out of hand
Why do wildfires in the Los Angeles Basin get lots of media coverage?
They threaten the homes of celebrities
What type of vegetation is much of the Los Angeles Basin covered in?
Drought-resistant chaparral
What type of wind increases the threat of forest fires in the Los Angeles Basin?
A dry wind called Santa Ana that descends from the local mountains and increases the dryness of the vegetation so that it can spark
The wind can also encourage the spread of fire
What further increases the issue of wildfires in Los Angeles?
Much of the area outside the centre of Los Angeles consists of low-density building where the natural vegetation has been allowed to remain between properties, exposing a large number of properties to the fire risk
What are the 6 direct effects of wildfires?
Loss of crops, timber and livestock Loss of life Loss of property Release of toxic gases and particulates Loss of wildlife Damage to soil structure and nutrient content
How much money is spent per day fighting wildfires in the USA?
$10 million
How many people lost their lives in the Victoria bushfires?
173
When were the Victoria bushfires?
2009
Why do some people die in forest fires?
Some fires move so fast that people become trapped
Why are urban areas becoming more susceptible to fires?
Due to urban expansion
What is the Southeast Asia ‘haze’?
A fire-related large-scale air pollution that occurs regularly
What causes the Southeast Asia ‘haze’?
Illegal agricultural fires due to slash-and-burn practices in Indonesia
Which countries are affected by the Southeast Asia haze?
Indonesia, Malaysia, Singapore, Thailand and Vietnam
What have the governments of the countries affected by the Southeast Asia haze demanded?
That Indonesia takes action against companies that are responsible for the illegal forest fires.
What did fires destroy in Indonesia in 1997?
The Wein River orangutan sanctuary on Kalimantan
Why can soil structure and nutrient content be damages by fires?
Due to the heat
What are the 7 ways in which the effects of wildfires can me mitigated?
Managing the vegetation Managing the built environment Modelling Education Warning systems Community action Insurance
Explain how vegetation can be managed
Controlled burning removes much of the litter
Fire breaks in the vegetation are made in advance
How is the built environment managed?
Gaps between houses and vegetation
Incorporating fore-resistant methods into construction (use stone or brick instead of wood and fit spark arresters to chimneys)
How does modelling work?
Involves studying the ways in which fires behave with computer simulations in order to comprehend and predict fire behaviour
How can warning systems be put into place?
Establishing look out towers
Air patrols
Notice boards
How may lives were lost in the 1983 Victoria fires?
47
How many homes were destroyed in the 1983 Victoria fires?
Over 2000
How much did the Victoria fires in 1983 cost?
Around AU $200 million
What programme was established as a result f the 1983 Victoria fires?
Community Fireguard
What was the purpose of Community Fireguard?
To assist people in developing their own fire survival strategies
Is Community Fireguard top down or bottom up?
It is more bottom up as the authorities tried to avoid using the top down approach that they had used before
What fire survival techniques did the local residents set up as a result of Community Fireguard?
Buffer zones Warning systems Brush and street clean ups Equipment training sessions Preparing emergency plans
How do authorities deal with wildfire events?
Spray water and chemicals from the ground and air (costly)
Beat out flames
Bull dozing large breaks in vegetation
Use of retardants
What do retardants do?
Slow down the pace of the fire
Where are retardants used?
In areas that are fairly inaccessible
Where human safety and structures are endangered
Where are trees replanted after such events?
In commercial forestry areas
Why are trees replanted in commercial forestry areas?
To improve the economy of the areas affected by fire
Why are trees planted on unprotected slopes?
To try and stabilise slopes which could otherwise experience mudslides as a result of flash flooding
To improve water quality
