FIRE EFFECTS ON CALIFORNIA CHAPARRAL SYSTEMS - AN OVERVIEW

Chaparral is a shrubby, sclerophyllous vegetation type that is common in middle elevations throughout much of California. It occupies 3.4 Mha throughout the state in some of the steepest terrain and adjacent to some of the most populated urban areas. Although chaparral has little direct commodity value, it does have great value in slope stabilization, watershed cover, wildlife habitat, and nutrient cycling. Combined effects of the summer-dry climate and the high flammability of chaparral vegetation render it extremely susceptible to periodic crown fires. Fires in the urban interface not only impact the chaparral ecosystem, but may burn homes, and also can affect regional air and water quality. Wildfires remove plant crown cover and may alter vegetation composition. Many chaparral plant species are well adapted to regenerate after fire, either through the ability to sprout vegetatively, or through fire-related cues that enhance germination. Fire also alters animal habitat and affects species composition and population levels. Perhaps most dramatic are the postfire effects on water and sediment movement. Flooding and debris flows which are common in years after fires may cause substantial loss of soil and nutrients and major damage to homes and other structures.