A boom arm cutting disk device for using a full area of a boom arm mounted cutting disk to cut materials facilitating vertical cutting and mulching of trees, brush, or the like. The device includes a disk configured for mounting on a boom arm such that the disk is rotatable relative to the boom arm. Each of a pair of cutters is coupled to and extends from the disk. Each of the cutters has a respective interior side edge aligned with a center of the disk and a respective blade edge extending outwardly from the interior side edge. Each blade edge defines a leading edge of the cutter as the disk is rotated wherein the cutters are configured to cut material by contact with the leading edges as a central area of the disk is urged towards the material while the disk is rotated.
