Abstract: An apparatus for transferring rows of side-by-side elongated members from a conveyor to a stacking platform to form bundles. A plurality of parallel stacker arms are displaceable in a direction parallel to the conveying of the elongated members, between a retracted position, and a stacking position, wherein the stacker arms are positioned above the stacking platform for disposing rows of elongated members thereon. A ramp is displaceable between an inclined position and a horizontal position, for guiding the pivoting of the stacker arms about carriages, such that stacker arms moving from the retracted portion to the stacking position are pivoted upward to pick up a row of elongated members from the conveyor portion, and that stackers arms moving from the stacking position to the retracted position are kept generally horizontal, so as to encompass the rows of elongated members conveyed on the conveyor portion. A slat positioner is also disclosed.