Help prune St Francis's town treetop (6)
I believe the answer is:
assist
'help' is the definition.
(to assist someone is to help them)
'prune st francis's town treetop' is the wordplay.
I cannot really understand how this works, but
'st' is present in the answer.
The remaining letters 'assi' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for assist that I've seen before include "Be useful to" , "Work as a subordinate" , "benefit" , "Pitch in" , "Help member" .)