Abstract: There is disclosed saw mill apparatus for cutting root end defects from lumber pieces and cutting such pieces to desired sizes including a generally conventional scanner for recording detailed contour data for each piece as it is moved by a plurality of chain belt conveyors transverse to its longitudinal dimension; the scanner is followed by a root end trim saw unit extending over the root end edge of such conveyors including a motor driven rotating circular saw blade articulated to move down into or up out of the path of lumber pieces and also slidably mounted to be moved over a range of about 24 inches in one half inch increments thereby to cut away a defective portion of a lumber piece identified by the scanner and a conventional mill computer; following the end trimming saw unit is an even ending apparatus with generally conventional ending rolls to transport lumber pieces lengthwise as necessary to butt the root end against a guide fence.