California Code, Fish and Game Code - FGC § 10740

It is unlawful for any person other than a legally constituted peace officer or officer or employee of the Forest Service of the United States Department of Agriculture, the department, or of the Department of Forestry and Fire Protection, or county fish and game wardens or their duly authorized representatives, to travel by motor boat, automobile, motorcycle, or other type of motorized vehicle, or, except for emergencies and for rescue and aerial search for rescue purposes, to land an airplane, helicopter, or similar equipment, within the boundaries of a primitive, wilderness, or wild area closed to the above modes of travel as established by a duly authorized officer of the Forest Service of the United States Department of Agriculture and recorded in the office of the Regional Headquarters of the Pacific-Southwest Region of the Forest Service of the United States Department of Agriculture and with the department.