Trees brought back from Alaska originally (4)
I believe the answer is:
oaks
'trees' is the definition.
(oak is a kind of tree)
'back from alaska originally' is the wordplay.
'back' shows that the letters should be reversed in order.
'from' indicates a hidden word.
'skao' is hidden in the letters of 'alaska originally'.
'skao' written backwards gives 'OAKS'.
'brought' is the link.
(Other definitions for oaks that I've seen before include "Acorn producers" , "Horse race - trees" , "Acorn trees" , "material for shipbuilding" , "Trees of the genus Quercus" .)