There was no wood on the bottom of the seat spring, are you talking about the piece of wood that went across the middle (side to side) of the seat riser? The back spring rests against four upright wooden slats with 2 hooks on the bottom of the out side pieces and the top of the spring is compressed and snaps into a groove on the bottom of the piece of wood that goes across the top on the back panel. Do a search and there should be some pictures as it has been covered here before, some of the info is under ccpu also as it is the same except for the wood strip at the top (the ccpu has 2 curved tabs at the top bolted to the strip that hold the lower and top center panels together)