Box fastener in wood (8)
I believe the answer is:
chestnut
'wood' is the definition.
(I know that chestnut is a type of wood)
'box fastener' is the wordplay.
'box' becomes 'chest' (chest is a kind of box).
'fastener' becomes 'nut' (a nut fastens things).
'chest'+'nut'='CHESTNUT'
'in' acts as a link.
(Other definitions for chestnut that I've seen before include "''Underneath the spreading . . . . . . . . tree''" , "Old story" , "Conker tree - 11 of 10" , "Hunt sect behind a big tree" , "Golden-brown or reddish-brown horse" .)