A road flanked by parrots in trees (8)
I believe the answer is:
pollards
'trees' is the definition.
(pollard is a kind of tree)
'a road flanked by parrots' is the wordplay.
'road' becomes 'rd' (abbreviation).
'flanked by' means one lot of letters goes inside another (other letters go on other side).
'parrots' becomes 'polls' (poll is a kind of parrot).
'a'+'rd'='ard'
'ard' placed inside 'polls' is 'POLLARDS'.
'in' acts as a link.
(Other definitions for pollards that I've seen before include "Trims tree to encourage new growth" , "trees cut back" , "Cuts trees back to promote bushy growth" .)