A device for displacing timber pieces longitudinally by adjustment of the timber pieces, comprising a cross conveyor equipped with a driver on which the timber pieces are conveyed in a cross direction, stops provided to bear against one face of the timber pieces and thereby displace the timber piece longitudinally during part of the transport of the timber pieces by means of the cross conveyor, a continuous track with which the stops are driven synchronously with the cross conveyor along it and wherein each stop travels in front of the respective driver of the cross conveyor along part of its feeding track, wherein the stops are displaceably mounted on units that are oriented across the continuous track and transferable along it, displacement means arranged to displace the stops in a positioning area (X, Z) in a cross direction against the transfer along the track and in the longitudinal direction of the timber pieces for displacement also of the timber pieces in the longitudinal direction, wherein each timber piece is displaced in its longitudinal direction on the cross conveyor with a via discontinuous control optional combination of stops and displacement means, whereby the displacement means comprise, at least two, in the cross direction of the continuous conveyor, displacement means (5:1, 5:2, 5:3) variable independently of each other, a docking device comprising a guide (13:1, 13:2, 13:3) for each displacement means (5:1, 5:2, 5:3) with a first end respectively a second end, characterised in that each guide (13:1, 13:2, 13:3) is adjustable via parallel transfer relative to the travelling direction of the stops on the continuous track and thereby across a width of the positioning area (X, Z) in the cross direction of the continuous conveyor, a first follower provided for each stop, which can be caused to be in guided interaction with a guide (13:1, 13:2, 13:3) through mutual setting of states, wherein said follower respectively guide meet at a transfer point in a state where they are situated in front of each other, an entry end to the positioning area (X, Z), wherein said entry end forms a defined zero reference (0-ref) for adjustment with respect to the positioning area width for each stop that successively arrive at the positioning area, and which stops can be caused to interact with any guide (13:1, 13:2, 13:3) the state of which is set at said transfer point. wherein each timber piece is displaced in its longitudinal direction on the cross conveyor with a via discontinuous control optional combination of stops and displacement means, whereby the displacement means comprise, at least two, in the cross direction of the continuous conveyor, displacement means (5:1, 5:2, 5:3) variable independently of each other, a docking device comprising a guide (13:1, 13:2, 13:3) for each displacement means (5:1, 5:2, 5:3) with a first end respectively a second end, characterised in that each guide (13:1, 13:2, 13:3) is adjustable via parallel transfer relative to the travelling direction of the stops on the continuous track and thereby across a width of the positioning area (X, Z) in the cross direction of the continuous conveyor, a first follower provided for each stop, which can be caused to be in guided interaction with a guide (13:1, 13:2, 13:3) through mutual setting of states, wherein said follower respectively guide meet at a transfer point in a state where they are situated in front of each other, an entry end to the positioning area (X, Z), wherein said entry end forms a defined zero reference (0-ref) for adjustment with respect to the positioning area width for each stop that successively arrive at the positioning area, and which stops can be caused to interact with any guide (13:1, 13:2, 13:3) the state of which is set at said transfer point.