One who provides tree transported in vehicle (7)
I believe the answer is:
caterer
'one who' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'tree transported in vehicle' is the wordplay.
'transported' is an anagram indicator.
'in' indicates putting letters inside.
'vehicle' becomes 'car' (car is a kind of vehicle).
'tree' is an anagram of 'tere'.
'tere' inserted inside 'car' is 'CATERER'.
'provides' is the link.
Can you help me to learn more?
(Other definitions for caterer that I've seen before include "Food and drink supplier" , "Provider of food and drinks" , "Provision supplier" , "Refreshment supplier" , "Purveyor" .)