Abstract: A stump cutting apparatus which may be mounted on a watercraft such as a barge and includes a rotating cutting drum having multiple cutter blades and driven by at least one hydraulic motor mounted on a boom extending from the barge. In a preferred embodiment the boom is connected to a linkage arm and the rotating drum is rotatably mounted on a pair of cooperating mount plates fixedly spaced by a spacer plate and pivotally attached to the boom and linkage arm to facilitate adjustment of the rotating drum upwardly or downwardly with respect to the extending end of the boom, while maintaining the cutting drum and spacer plate in horizontally parallel relationship. A pair of arm hydraulic cylinders have their cylinder ends attached to mount brackets provided on the respective mount plates and the cylinder pistons connected to a stabilizing arm pivotally attached to the mount plates for stabilizing the cutter blade against a stump or tree during the cutting operation.