Manage to surround small thicket (5)
I believe the answer is:
copse
'thicket' is the definition.
(I know that thicket can be written as copse)
'manage to surround small' is the wordplay.
'manage' becomes 'cope' (manage can mean to cope or do well).
'to surround' is an insertion indicator.
'small' becomes 's' (abbreviation - e.g. clothes size).
'cope' placed around 's' is 'COPSE'.
(Other definitions for copse that I've seen before include "Cluster of trees" , "Small thicket" , "Harvested woodland" , "Scope for a small wood" , "spinney" .)