The first public hearing, concerning a requested zone change in Pioneertown, will take place before the San Bernardino County Board of Supervisors tomorrow at 3 p.m. The hearing, requested on petition of actor Russell Hayden, one of the original Pioneertown developers, is for consideration of a zone change from rural residence (RR) to desert living (DL) in portions of section 20, Township 1 North, Range 5 East. The portions lie both north and south of Pioneertown Road and in the vicinity of Skyline Ranch Road.