Chemical destroying trees (5)
I believe the answer is:
ester
'chemical' is the definition.
(thesaurus)
'destroying trees' is the wordplay.
'destroying' indicates anagramming the letters.
'trees' with letters rearranged gives 'ESTER'.
(Other definitions for ester that I've seen before include "Reset (anag.)" , "Compound formed from acid and alcohol" , "Chemical compound of acid and alcohol, found in trees" , "radical" , "Fat" .)