Lumber from the seat (6)
I believe the answer is:
saddle
This clue is a double definition.
'lumber' is the first definition.
(thesaurus)
'the seat' is the second definition.
(saddle is a kind of seat)
'from' is the link.
(Other definitions for saddle that I've seen before include "load" , "Equestrian equipment" , "Seat for a horseman" , "Jockey's seat" , "Lamb joint" .)