Exchange views about one tree (7)
I believe the answer is:
conifer
'tree' is the definition.
(conifer is a kind of tree)
'exchange views about one' is the wordplay.
I cannot quite understand how this works, but
'about' could be 'on' (as in a book 'on' a certain topic) and 'on' is found in the answer.
'one' could be 'er' (I've seen this in other clues) and 'er' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for conifer that I've seen before include "Eg, pine, fir or cypress" , "one branching out" , "E.g. yew, pine or fir" , "Type of tree" , "The tree doesn't lose its leaves" .)