Tree planted by person who is a municipal councillor (8)
I believe the answer is:
alderman
'a municipal councillor' is the definition.
(I know that alderman is a type of municipal councillor)
'tree planted by person' is the wordplay.
'tree' becomes 'alder' (alder tree is a kind of tree).
'planted by' says to put letters next to each other.
'person' becomes 'man' (man is a kind of person).
'alder'+'man'='ALDERMAN'
'who is' acts as a link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for alderman that I've seen before include "superior member of county council" , "Member of an English city council" , "Member of a local legislative body" , "Civic officer" , "Bigwig" .)