brushwood vs leaf litter

brushwood

noun
  • Branches and twigs fallen from trees and shrubs. 

  • Small trees and shrubs. 

leaf litter

noun
  • Dead plant material, such as fallen leaves, bark, and twigs, that has fallen to the ground and may be used by animals as habitat or for nest-building, eventually decomposing and releasing nutrients into the soil. 

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