Sonoma County Fire Chief Al Terrell, brought in three years ago by the Board of Supervisors to help guide big changes that could reshape the purpose and look of the county’s Fire and Emergency Services Department, announced Wednesday he intends to resign at the end of July, before any of those changes are rolled out. The planned departure of the county’s top fire chief comes as supervisors and fire officials countywide face options this year that could result in the 11 remaining volunteer fire companies leaving county administration and a stronger push toward consolidating the county’s 37 public fire agencies.