Supported small tree that has given up the ghost (8)
I believe the answer is:
steadied
'supported' is the definition.
(to steady is to support or make stable)
'small tree that has given up the ghost' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'tree' becomes 'tea' (I've seen this before).
'that has' is a charade indicator (letters next to each other).
'given up the ghost' becomes 'died' (to 'give up the ghost' is to die).
's'+'tea'+'died'='STEADIED'
(Other definitions for steadied that I've seen before include "made stable" , "Made firm and balanced" , "Supported, controlled" , "calmed down" , "Braced" .)