Stump at bottom of forest (5)
I believe the answer is:
floor
I believe this is a double definition.
'stump' is the first definition.
(I've seen this before)
'at bottom of forest' is the second definition.
(I've seen this before)
(Other definitions for floor that I've seen before include "Knock down; storey" , "American story" , "Knock down - planking" , "Bottom surface" , "Disconcert" .)