Tree maintenance check (7)
I believe the answer is:
service
I believe this clue is a double definition.
'tree' is the first definition.
(service tree is a kind of tree)
'maintenance check' is the second definition.
(eg a boiler service)
(Other definitions for service that I've seen before include "Work done by one for the benefit of another" , "Waiting" , "See 4" , "Act of worship" , "Tennis opening shot" .)