underbrush vs woods

underbrush

noun
  • The small trees and other plants that clutter the floor of a forest. 

verb
  • To clear (an area) of underbrush. 

  • To work among the underbrush. 

woods

noun
  • A dense collection of trees, usually one covering a relatively small area; usually smaller than a forest. 

  • For chemical behavior purposes, trees in full leaf (coniferous or medium-dense deciduous forests). 

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