Cal. Pub. Res. Code § 4252

Upon the written petition of the owners or authorized agents of more than 50 percent of the land, including public land, within the exterior boundaries of any area of not less than 10,000 acres in size, upon which a fire hazard exists due to the presence of flammable material or cover, the board may designate such area as a hazardous fire area, and shall declare the period of time during which the area shall be so designated.