EARTHSC 2GG3 Lecture 9: Natural disasters -Lecture 9 - Wildfires
16 Jun 2016
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Document Summary
Introduction: dating back more than 350 million years. Before humans, fire would burn until they ran out of fuel naturally. After a fire, colonizing plates become established on the burned landscape. Natural fires allowed humans to harness fires for heat, light, and cooking. If any of these is removed, the fire goes out. Vegetation is brought to a temperature and water content at which it can ignite and: fuel, oxygen, heat burn, pre heating, pyrolysis. Vegetation loses water and other chemical compounds: wildfires only develop when vegetation is dry and has accumulated in. Involves external reactions that liberate heat and light. Ignition does not necessarily lead to a wildfire. Processes that chemically degrade the preheated fuel. Products include volatile gases, mineral ash, tars, and char. Heat radiating from flames causes preheating and pyrolysis in advance of the fire. Convective and radiant heating increase the surface temperature of the fuel.
