Stacks of wood (4)
I believe the answer is:
deal
This clue is a double definition.
'stacks' is the first definition.
(thesaurus)
'wood' is the second definition.
(deal is a kind of wood)
'of' acts as a link.
(Other definitions for deal that I've seen before include "Transact" , "Agreement; hand out cards" , "Put cards on table" , "Softwood - business transaction" , "A port; a (good) amount" .)