Acorn bearers (4)
I believe the answer is:
oaks
'acorn bearers' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for oaks that I've seen before include "Mighty ones from little acorns grow" , "Soak up with trees" , "Acorn trees" , "Acorn producers" , "Hardwood trees" .)