The influx of humans and equipment into new wildland areas increases risk. Fuel characteristics help determine how a wildfire burns. The fuel condition determined for an area makes up fuel hazard which is not to be confused with fire risk. Fuel size is measured by the number of hours it takes the fuel to reach equilibrium with the relative humidity in the air. One hour fuels dampen or dry quickly.
Dead grass is a one hour fuel.
Very small twigs and branches are examples of 10-hour fuels. Fuel quantity is simply the amount of all fuel sizes located on an area of land. It is usually expressed in tons per acre. Fuel arrangement generally refers to density and compactness of fuel. Cut and drying hay is lower to the ground and is somewhat compressed or pushed down.