grove vs underbrush

grove

noun
  • A small forest. 

  • A place of worship. 

  • An orchard of fruit trees. 

  • A lodge of the Ancient Order of Druids. 

verb
  • To cultivate in groves; to grow naturally so as to form groves. 

  • To plough or gouge with lines. 

  • To cultivate with periodic harvesting that also serves to create order (gaps and lines of trees) to facilitate further harvesting. 

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. 

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