Fire

The mastery of fire separates humans from other animals. Our use of this chemical reaction—on landscapes, in hearths, and in industry—is one of our most fundamental and influences on the environment. Without fire, many of our foods and landscapes would be unrecognizable. But fire also destroys homes and habitats, and inspires or even expresses conflict between different people.

Fire is a chemical chain reaction akin to photosynthesis in reverse. Once sufficiently heated, fuels react with oxygen in the air to produce carbon dioxide, [Page 668]water vapor, and heat energy. The size, type, and moisture content of fuels, as well as the prevailing weather conditions (humidity, precipitation, temperature, and wind), are crucial in affecting the threshold for ignition and potential for spread. The most common fuels for ...