Left them out of the wood (3)
I believe the answer is:
elm
'wood' is the definition.
(elm is a type of tree)
'left them out of' is the wordplay.
'left' becomes 'l' (common abbreviation).
'them' becomes 'em' (abbreviation).
'out of' is an insertion indicator (some letters on the outside of others).
'l' inserted into 'em' is 'ELM'.
'the' acts as a link.
(Other definitions for elm that I've seen before include "Wood in pelmet" , "Leaving body" , "Tree with winged fruit" , "Stately tree" , "Kind of tree" .)