Abstract: A tree saw includes a frame adapted to be attached to the boom of a prime mover, a tree clamping mechanism on the frame, and a carriage assembly on the frame below the clamping mechanism. The carriage assembly includes a generally plate-like chassis, a generally U-shaped bulkhead upstanding from the chassis and providing a recessed base portion and forwardly-extending arm portions, and a slide mechanism on the arm portions. A rail mechanism on the frame receives the slide mechanism for reciprocating movement of the carriage assembly. A hydraulic cylinder assembly interconnects the bulkhead and frame for reciprocating the carriage assembly. An annular rim member rotatably mounted on the chassis has a geared inner circumference and a toothed outer circumference projecting forwardly of the base portion. A motor-driven pinion mechanism on the chassis engages the rim member inner circumference to rotate the rim member.