Destruction of conifers, legal (8)
I believe the answer is:
forensic
'legal' is the definition.
(thesaurus)
'destruction of conifers' is the wordplay.
'destruction of' is an anagram indicator.
'conifers' anagrammed gives 'FORENSIC'.
(Other definitions for forensic that I've seen before include "may be referred to court" , "As scientific tests in crime fighting" , "type of medicine?" , "legal practice" , "Using science to investigate crime" .)