Endure abuse, protect tree when attacked (5,4)
I believe the answer is:
under fire
'attacked' is the definition.
Both the definition and answer are adjectives. Perhaps there's a link between them I don't understand?
'endure abuse protect tree' is the wordplay.
'abuse' indicates an anagram.
'protect' is an insertion indicator.
'tree' becomes 'fir' (fir is a kind of tree).
'endure' is an anagram of 'undere'.
'undere' going around 'fir' is 'UNDER FIRE'.
'when' acts as a link.
Can you help me to learn more?
(Other definitions for under fire that I've seen before include "Being shot at" , "subject to criticism" , "exposed to criticism" , "Make half-baked" , "Military situation, at the bottom of the grate?" .)