Abstract: A lumber stacking apparatus for successively placing layers of boards one on another to form a vertical stack, and for automatically placing stickers between successive layers of boards to vertically separate the layers within the stack. The successive layers of boards are formed along a layer support surface adjacent the stack. A forked arm assembly is raised to lift the formed layer from the layer support and carry the lifted layer to the stack and deposit the layer on the stack. The stickers are initially moved transverse to the movement of the fork arms to selected sticker positions. The stickers are then lifted up and over sticker supports provided on the sides of the fork arms. As the fork arms are raised to lift of layer of boards from the layer support surface, the sticker supports simultaneously lift a layer of stickers against the bottom side of the board layer.