How is fuel moisture defined in the context of wildland fire?

In the context of wildland fire, fuel moisture is defined as the amount of water contained in fuel, expressed as a percentage of the fuel's over-dry weight. This measurement is crucial because it influences how easily and quickly a fire can ignite and spread. When fuel moisture is low, the material is drier and more flammable, making it easier for fires to start and grow. Conversely, higher fuel moisture levels indicate that the fuel is wetter, which can suppress fire behavior and reduce the likelihood of ignition.

Understanding fuel moisture helps fire managers assess fire risk and plan appropriate responses to wildfires. It also plays a vital role in predicting fire behavior, as the moisture content of fuels can change with environmental conditions, such as humidity and recent precipitation. This percentage relationship provides a standardized way to communicate and understand the flammability of various fuels in wildfire scenarios.