ENT aid finds a tree wrecked round ex Pres. (3-7)

'wrecked round ex pres' is the definition.
I can't judge whether this defines the answer.

'ent aid finds a tree' is the wordplay.
I cannot really understand how this works, but
'a' is within the answer.
'tree' could be 'trumpet' (trumpet tree is a kind of tree) and 'trumpet' is present in the answer.
The remaining letters 'er' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?