"Tree person" on plantation (8)
I believe the answer is:
mangrove
'tree' is the definition.
(mangrove is a kind of tree)
'person on plantation' is the wordplay.
'person' becomes 'man' (man is a kind of person).
'on' says to put letters next to each other.
'plantation' becomes 'grove' (both can mean a wood).
'man'+'grove'='MANGROVE'
(Other definitions for mangrove that I've seen before include "Evergreen" , "whose roots may be waterlogged" , "Shrub" , "that grows in swamps" , "Tree of coastal swamps" .)