underbrush

noun

1. (uncountable, usually)The small trees and other plants that clutter the floor of a forest.

   “How quick the eye and hand to catch him [the ruffed grouse] when he rises from the underbrush and is out of sight in the wood before the untrained sportsman stops him with what is little more than a snapshot, so instantaneously must all be done!”

verb

1. (transitive)To clear (an area) of underbrush.
2. (intransitive)To work among the underbrush.