Framework / Assessment California Forests and Rangelands: 2015 Assessment Summary Patterns and types of fires can depend on the type of dominant vegetation in an area. Fire frequency is an important characteristic of fire regimes for particular vegetation types. If a fires normally occur frequently for a particular type of vegetation in an area, but now occur infrequently, this can lead to increased risk of fire and fire severity in the future. The degree of departure of fire regimes from a normal range indicates risk from wildfire.