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Fire – The rapid combination of oxygen, hydrogen, and other elements of organic material in a reaction that produces flame, heat, and light.
Fire is necessaryIn some environments, decomposition cannot keep up with the production of plant material.
• 2009 Statistics from the CDC
• 2565 deaths, mostly from smoke and toxic gases, not burns.
• 85% in homes
Fuel Categories
• Grasses• Shrubs• Trees• Slash
Ladder fuels – when liter and shrubs act as a ladder for fire to climb up into the crowns of trees.
Pyrolysis• Flaming combustion – When wood surface
heats up to ~3250C (6150F), it breaks down and produces gases that support flames.
Spread of Fire
• Fuel – Energy release in a fire depends on chemical composition of plants and organic debris. Example: oils of eucalyptus trees.
• Wind – strong wind causes…1. Continuous supply of oxygen to the fire.2. Pushes flames and heat towards more fuel.3. Produces firebrands that can start spot fires.
• Fire Behavior 1. Fire causes hot, unstable rise of air.2. This can produce fire tornadoes with winds of up to 250kph (150mph).
http://www.youtube.com/watch?v=cGvTgYyANy8
• Cold fronts – As cold fronts move through the West in summer, they may produce lots of lightning but little rain.