Dry grasses, leaves, twigs, needles, shrubs or trees easily consumed by fire. More fuels cause a fire to burn faster and more intensely. Ground Fire Burning organic soil which sometimes burns several inches to several feet under ground. Ground Fires are often difficult to detect and can burn for extended periods of time.
Any material substance that can be consumed to supply heat or power. Included are petroleum, coal, and natural gas (the fossil fuels), and other consumable materials, such as uranium, biomass, and hydrogen.