Which kind of fuel includes brush that is up to 6 feet tall?

Surface fuel refers to the materials that are found on the ground, including grass, leaves, fallen branches, and brush. Brush up to 6 feet tall falls within this category as it is considered part of the surface fuel layer that can easily ignite and contribute to the spread of fire. Surface fuels are in direct contact with the flame and are often the first to catch fire, playing a crucial role in fire behavior and intensity.

Subsurface fuel typically refers to organic matter found beneath the surface, such as roots and decaying material, which may contribute to smoldering combustion rather than active flame. Aerial fuel involves vegetation above the ground, such as tree canopies and tall grasses, which are usually higher than 6 feet. Ground fuel includes materials under the surface, such as peat and duff, and does not include brush. Understanding these distinctions is essential for fire suppression strategies and predicting fire behavior.