How does the rate of spread (ROS) of brush fuel compare to that of grass?

The rate of spread (ROS) of brush fuel compared to grass is often slower but typically generates a higher intensity of heat and combustion. Brush consists of thicker, denser materials, which, while they may not ignite as quickly as grass, often burn with more intensity due to their higher moisture content and the type of organic materials present. This results in more heat release, allowing brush fires to create more intense fire behavior, especially when compared to the generally faster spreading, lower intensity fires of grass.

Grass fires can spread quickly due to the lighter and dryer nature of the fuel, which allows flames to move rapidly through fine grasses. However, while the flames may travel faster, the overall heat energy produced per unit of fuel burned tends to be lower compared to the denser brush species, which contribute to more intense burning conditions once ignited. In essence, while the rate of fire spread may be faster in grass fuel, the higher intensity burning of brush during its slower ROS is crucial in understanding fire behavior and planning effective wildfire mitigation strategies. This difference in fire dynamics highlights the need for tailored approaches to management and suppression based on the type of fuel present.