A miniature plane, perhaps (5,4)
I believe the answer is:
Here is my best explanation:
'a miniature plane perhaps' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.
'miniature plane perhaps' is the wordplay.
'miniature' becomes 'dwarf' (I can't explain this - if you can you should believe this answer much more).
'plane perhaps' becomes 'tree' (I've seen this in other clues).