A press assembly for fibrous substance including a tramper assembly with a tramping chamber and a tramper, the tramper being movable along a length of the tramping chamber, and a main compressor including a main compression box and a follow block, the follow block being movable along a length of the main compression box. The tramping chamber and the main compression box are in communication with each other such that fibrous substances disposed within the tramping chamber can pass directly from the tramping chamber to the main compression box