Most gentle incline with replanted trees (9)
I believe the answer is:
tenderest
'most gentle' is the definition.
(I've seen this before)
'incline with replanted trees' is the wordplay.
'incline' becomes 'tend' ('tend' can be a synonym of 'incline'**).
'with' says to put letters next to each other.
'replanted' indicates anagramming the letters (letters get placed or planted in new positions).
'trees' with letters rearranged gives 'erest'.
'tend'+'erest'='TENDEREST'
(Other definitions for tenderest that I've seen before include "least macho?" , "most sore" , "Most sympathetic" , "Most compassionate" , "Most gentle" .)