Abstract: A swing-to-tree feller buncher has its boom swing-house assembly adjustably supported from its track carriage frame by a leveling mechanism which includes a front link, a rear link, and a pair of laterally spaced apart hydraulic cylinders. Both links are fixed to the frame toward the front of the carriage and the front link is shorter than the rear link. The upper ends of the hydraulic cylinders connect to the turntable support of the swing-house assembly at a position forward of the rear link and extend rearwardly to connect at their lower ends to the frame of the carriage at a position which is rearward of the rear link. The turntable support is also pivotable from side to side relative to the carriage about a minor axis.