Ranger, perhaps, in favour of development of trees (8)
I believe the answer is:
forester
'ranger perhaps' is the definition.
'in favour of development of trees' is the wordplay.
'in favour of' becomes 'for' (I've seen this before).
'development of' is an anagram indicator (I've seen 'development' mean this).
'trees' is an anagram of 'ester'.
'for'+'ester'='FORESTER'
(Other definitions for forester that I've seen before include "One in charge of woodlands" , "One caring for trees" , "Tree expert" , "Woodman" , "Hornblower novelist" .)