Abandon key trees, felled (6)
I believe the answer is:
desert
'abandon' is the definition.
(desert can mean to leave or abandon)
'key trees felled' is the wordplay.
I cannot really understand how this works, but
'key' could be 'd' (musical key) and 'd' is located in the answer.
an anagram of 'trees' is 'esert' which is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for desert that I've seen before include "Defect, forsake" , "desolate place" , "Callously abandon" , "See 23" , "Barren area" .)