California state law requires homeowners in wildfire prone areas to create defensible space around their homes. Defensible space is created by altering the type and location of vegetation surrounding a home so that it is defensible by fire fighters during a wildfire. This law is enforced by the California Department of Forestry & Fire Protection.
Specific recommendations for creating defensible space vary by location, however, The Combustibility of Landscape Mulches publication, shows some general principles hold true everywhere. To learn more about how to create defensible space, please see this University of California Cooperative Extension publication: Home Landscaping for Fire. Also, check out the information on UCCE Fire in California's website about characteristics of different mulches.
National guidelines can also be found through the Fire Wise program developed by the National Fire Protection Association which encourages local solutions for wildfire safety by involving homeowners, community leaders, planners, developers, firefighters, and others in the effort to protect people and property from the risk of wildfire.
Place based recommendations are available from fire agencies and fire safe councils in most communities. Go to the Living with Fire in the Lake Tahoe Basin for specific recommendations.
California's fire safe councils are very involved in defensible space and forest fuels reduction projects and are a great resource for expertise, funding and collective action to reduce wildfire risk. See the Fire Safe Councils in the Central Sierra.