Landmines literally in trees (4)
I believe the answer is:
elms
'in trees' is the definition.
'elms' can be an answer for 'trees' (I've seen this in another clue). I am not sure about the 'in' bit.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for elms that I've seen before include "Mel's strange trees" , "may have many leaves" , "Trees sound like Cockney steering devices" , "Trees (of late, prone to disease)" , "rugged feature of country churchyard" .)