head of hair vs tress

head of hair

noun
  • All the hair that covers the scalp of a person (excludes the beard and moustache) 

tress

noun
  • A long lock of hair 

  • A braid, knot, or curl, of hair; a ringlet. 

  • A knot or festoon, as of flowers. 

verb
  • To braid or knot hair. 

How often have the words head of hair and tress occurred in a corpus of books? (source: Google Ngram Viewer )