Thicket of small trees (5)
I believe the answer is:
copse
'thicket of small trees' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for copse that I've seen before include "Wood - thicket" , "Small group of trees" , "Dense thicket of trees" , "spinney" , "Harvested woodland" .)