Argument against fire breaks with such a type of tree (7)
I believe the answer is:
conifer
'such a type of tree' is the definition.
(I've seen this before)
'argument against fire breaks' is the wordplay.
'argument' becomes 'con' (con is a kind of argument**).
'against' is a charade indicator (letters next to each other).
'breaks' is an anagram indicator.
'fire' is an anagram of 'ifer'.
'con'+'ifer'='CONIFER'
'with' is the link.
(Other definitions for conifer that I've seen before include "one branching out" , "E.g. yew, pine or fir" , "Tree such as pine, yew etc" , "In force (anag.)" , "Evergreen (generally)" .)