An apparatus for removing limbs from the trunk of a tree in which a hydraulically-activated compression ring operates to keep a segmented circular array of curved cutter blades in intimate branch-shearing contact with a tree trunk of variable size as said tree is fed endwise through the machine. The cutter knives are attached to the free ends of pivotally-mounted elongated support arms, and the compression ring is slidably attached to the outside of each of the support arms. The tree is pulled through the machine by hydraulically-powered, spiked rollers.