Fan had treen transported (8)
I believe the answer is:
adherent
'fan' is the definition.
(I've seen this before)
'had treen transported' is the wordplay.
'transported' indicates an anagram.
'had'+'treen'='hadtreen'
'hadtreen' with letters rearranged gives 'ADHERENT'.
(Other definitions for adherent that I've seen before include "Supporter; sticking" , "Loyal follower - sticks close" , "One believes in and helps spread the doctrine of another" , "Supporter, fan" , "Freak" .)