Row of trees in area in London somehow protected by church (9)
I believe the answer is:
colonnade
'row of trees' is the definition.
'colonnade' can be an answer for 'row' (I've seen this before). I am not certain of the 'of trees' bit.
'area in london somehow protected by church' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'in' means one lot of letters goes inside another.
'somehow' indicates anagramming the letters.
'protected by' indicates putting letters inside (inserted letters are held or protected).
'church' becomes 'CE' (Church of England).
'london' anagrammed gives 'olonnd'.
'a' put inside 'olonnd' is 'olonnad'.
'olonnad' placed inside 'ce' is 'COLONNADE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for colonnade that I've seen before include "Row of columns supporting a roof" , "Collection of columns" , "Row of evenly spaced pillars" , "Arcade" , "supporters in a row" .)