Fires in Nature

Wildfires

Wildfires

uncontrolled fires that occur in natural areas such as forests and grasslands

Ground fires

• Burn beneath the ground surface with tree roots and peat layers burning

• smouldering, slow-moving fires

• can burn for days and weeks with no visible flame and little smoke

surface fires

• burn through low-lying vegetation such as grass, bushes and small trees

• they are most common and can move quickly

crown fires

• burn through the canopy layer which is the top layer of vegetation

• most dangerous and destructive types of wildfire because they move quickly and often produce intense heat and flames

Distribution of wildfire

• wildfires occur over all the world

• not Antarctica

• most common in the tropics and subtropics

• common in large forested areas of dense vegetation

  • Russia, Canada and USA

Conditions of wildfires

• vegetation type

• fuel characteristics

• climate and recent weather

vegetation type

• Denser vegetation tends to lead to more intense fires that can spread quickly and burn for longer

  • forest fires tends to be more dangerous and intense than grassland fires

• some types of vegetation are more flammable than others

fuel characteristics

• the amount of available fuel, such as trees, grass and dead plant materials affects the likelihood and severity of fires

• fine and dry material such as grasses and twigs can catch fire and burn very easily

climate and recent weather

• dry weather and droughts dry out vegetation and increase flammability

• high temp and heat waves increases evaporation

  • dries out vegetation

• strong winds can cause fires to spread

• lightning storms can start fires

• climate change is increasing the frequency and severity of wildfires in many regions

fire behavior

• fire behaviour refers to physical characteristics

• intensity

• rate of spread

• flame length

• more intense fires with higher flames can ignite trees and other vegetation causing them to spread more quickly

• spread more quickly uphill due to strong winds and dry vegetation

• fires that have multiple fronts are more unpredictable

causes of wildfires

• wildfires are caused by both natural and human factors

• most caused by humans

• natural causes include lighting strikes, volcanic eruptions and heat from sun

• human causes include campfires, barbecues, cigarettes, power lines

• arson

social primary impacts

• death and injuries

• displacement of people

• damage to properties and infrastructure causing disruption to peoples life

• damage/ destruction of crops

economic primary impacts

• destruction of property and infrastructure leading to significant costs for repair and recognition

• disruption to trade and economic activity

• loss of crops and timber

• loss of income and employment

• cost of imediate responses

environmental primary impacts

• destruction of habitats

• loss of biodiversity

• atmospheric pollution from smoke and toxic gasses

• water pollution as ash gets into water

political primary impacts

pressure on governments to coordinate a emergency response

social secondary impacts

• mental health issues

• health issues e.g. respiratory

• homelessness

• food shortages

economic secondary impacts

• slower economic growth and development

• increased economic inequality as impacts are more severe for most vulnerable people

• increased cost of insurance and hazard management strategies

environmental secondary impacts

• long-term impacts of food webs and ecosystems

• increased soil erosion and leaching due to lack of trees and vegetation

• damage to soil and loss of soil fertility

• increased risk of flooding

• release of carbon emissions contributes to climate change

political secondary impacts

changes in forest management policies to reduce chances of fires

short term response

• firefighters work to contain and extinguish the fores as soon as possible

• warnings and evacuation warnings issued

• fire diverted away from settlements

• water sprayed onto land and building to reduce flammability

• search and rescue operations implemented

• monitoring of air quality to issue advisories about risk of respiratory illness

long term responses

• public education campaigns

• preparation and training of emergency services

• creating firebreaks in forested areas to reduce spread

• using less flammable materials in construction

• improvement of monitoring and warning systems

• restorations of damaged ecosystems

preparedness and adaptation

• satellites and infrared sensors can be used to improve early detection and monitoring

• warnings can be issued to allow time for evacuations

• evacuations plans made

• emergency kit planning

• education campaigns

Mitigation and prevention

• strategies can be implemented to reduce the chances of wildlife and extinguish them as quickly as possible

• fire fighters use helicopters and aeroplanes to drop water and fire retardants

• back-burning strategies where fires are lit ahead of fire to reduce fuel availability

• public awareness campaign and rules on campfires

• weather conditions monitoring

• alerts and fore bans can then be implemnetd to residents

• firebreaks

• controlled burning can reduce the amount of fuel

• improvement of infrastructure

• buildings code