fires in nature

• Wildfire


  A large, uncontrolled fire that quickly spreads through vegetation
• Conditions favouring intense wildfires

  • Vegetation type: Thick, close together vegetation allows fires to spread quickly and easily. Trees and thick bushes lead to more intense wildfires; grasslands do not burn as intensely. Vegetation with flammable oils - like eucalyptus - causes more intense fires also.
  • Fuel characteristics: Vegetation should be dry to allow it to catch. Finer vegetation causes fires to spread quicker, but larger, thicker forms of vegetation burns for longer and more intensely.
  • Climate and recent weather: Wildfires can occur anywhere in the world, but in a climate that has enough rainfall to have sufficient plant growth, but considerable dry spells and droughts to dry out the fuel. Areas with dry seasons such as California allow for intense wildfires. Wind also causes fires to spread quicker. Many climatic events can make wildfires grow more intense and extend wildfire seasons.
• Recent temperature increases have caused an increase in the number of wildfires and an increase the length of wildfire seasons. "Forest fires in the western US have been occurring nearly five times more often since the 1970s and 80s. Such fires are burning more than six times the land area as before, and lasting almost five times longer."
• There are also arguments that despite climate change, wildfires are not increasing everywhere. Studies have shown that this is somewhat true; between 1998 and 2015 globally burned area declined about 24 percent. However, this may also be down to agricultural productivity and land use change as there are less areas that can be burned, i.e. less forestry.
• Fire behaviour

  • Fires spread quickly on hills as the heat rises. Fire can also 'jump' across rivers and into areas due to lit debris which causes it to spread.
  • There are three main types of wildfire burning: Crown fires burn the entire tree from bottom to top, which is classed as the most dangerous and destructive type of fire. Surface fires only burn the leaf litter, meaning they are easy to extinguish. Ground fires burn at the dry peat or vegetation beneath the surface, and move slowly through the dried underground. Due to them being underground, they can be difficult to put out and can actually continue to burn throughout the year if the weather conditions allow it.
• Causes of wildfires

  • Natural causes: lightning (being the biggest cause), volcanoes and even spontaneous
  • Human causes: lit cigarettes, barbeques, agriculture, train lines and more
• Environmental effects

  • Primary: Air pollution from ash, Water pollution, Habitats destroyed in fire, Toxic gases released in burning
  • Secondary: Removing invasive species and stimulating seed germination, Migration patterns of animals affected, Increased CO₂ from fires could heighten the greenhouse effect
• Economic effects

  • primary: Businesses destroyed, Agricultural land damaged, Cost of fighting fires (firefighters, helicopters, water),
  • secondary: High cost of rebuilding and insurance payout, Sources of income lost, Discouraging visitors, losing tourism sector
• Social effects

  • primary: People killed or injured in fires, Homes destroyed, People go missing during evacuations,
  • secondary: Homelessness, Food shortages from destroyed agricultural land, Health problems such as asthma from smoke inhalation
• Political effects


  • primary: Government buildings destroyed
  • secondary: Borrowing money for international aid, Pressure for government to do more about global warming due to increased frequency
• Risk management: Prevention and preparedness

  Public awareness campaigns, Evacuation plans, Emergency services training and drills, Personal emergency plan, Warning systems, Thermal infrared satellite imagery
• Risk management: Mitigation


  1. Immediate responses: Search and rescue teams, Immediate aid, Evacuations, Extinguishing the fire (firefighters, water, flame retardants)

  2. Long-term strategies: Controlled burnings, Fire breaks, Reducing flammable materials around homes, Building homes with less harmful materials
• Adaptation


  Living with the consequences of wildfires, Expenses of insurance and clean-up, Staying educated, Reducing CO₂ emissions to stop contributing to the greenhouse effect
• There is the argument that perhaps we should not intervene in wildfires at all, which can be classed as a fatalistic outlook. Many people believe it is not worth the money or resources to extinguish wildfires if they are only going to start again, and some should just be left to burn. There are also ecological benefits of having wildfires burn, which supports the idea that we should adapt to wildfires and let them burn.
• Wildfires eradicate disease and stimulate seed germination. An example of where extinguishing wildfires may have done more harm than good is in Jasper, Alberta. Threatening wildfires have been frequently extinguished in the past, meaning the forest has become thick and deprived of light. This has then prevented the growth of silver birch and other trees, and the forest is now mostly pine. Due to no fires eradicating diseases or harmful insects, the Mountain Pine Beetle has taken over the forest, which has severely affected the ecosystem and caused many trees to die. Eventually, the species will cause the forest to be destroyed and then naturally regrow, which would have happened by natural wildfires anyway.