ancestry vs family tree

ancestry

noun
  • Condition as to ancestors; ancestral lineage; hence, birth or honorable descent. 

  • A series of ancestors or progenitors; lineage, or those who compose the line of natural descent. 

family tree

noun
  • The totality of someone's ancestors and offspring 

  • A diagrammatic representation of a pedigree, illustrating the connections between a person's ancestors, offspring and other relatives 

How often have the words ancestry and family tree occurred in a corpus of books? (source: Google Ngram Viewer )