Family tree help offered at librarySTOCKTON — The Margaret K. Troke Library is hosting a free beginner’s course on starting a family tree at 11 a.m. Feb. 20 at its branch at 502 W. Benjamin Holt Drive.Jacqi Stevens of the San Joaquin Genealogical Society, with help from other society members, will be available to offer tips and tools on researching your ancestry.