Abstract: An extendible tree trimmer includes an extendible tube unit with a motor and a cutting blade connected to the opposite ends. The tube unit includes a first housing and a telescopic second housing connected by a releasable coupling unit. A first shaft connected to the motor extends through the first housing and second shaft is telescoped with the first shaft and extends through the second housing to the cutting blade. The housings are releasably coupled for telescoped positioning. A rotary bearing supports the shafts in the housings. A gear reduction unit and a slip clutch unit connects the motor to the first shaft. The cutter head includes a rotating cam secured to the second shaft. The cam has a peripheral groove with axially offset portions and with a follower in said groove. The follower is secured to the blade which reciprocates in the plane of the blade. The blade has teeth on the opposed edges to cut with the blade moving toward the housing.