coppice vs understory

coppice

noun
  • A grove of small growth; a thicket of brushwood; a wood cut at certain times for fuel or other purposes, typically managed to promote growth and ensure a reliable supply of timber. See copse. 

verb
  • To manage (a wooded area) sustainably, as a coppice, by periodically cutting back woody plants to promote new growth. 

  • To sprout from the stump. 

understory

noun
  • The layer of plants that grow in the shade of the canopy of a forest. 

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