Abstract: There is disclosed electronic apparatus for devitalizing a band of cells girdling a tree trunk to cause the death of an unwanted tree or other plant, including a source of radio-frequency energy, and first and second r.f. electrical couplers to the stem or trunk of the plant or tree; preferably such couplers are flexible chains or the like and are caused to encircle the tree by a first actuator which closes jaws of a portable portion of the apparatus around the tree and a second actuator which draws the flexible couplers snug against the trunk of the tree. Death of the plant is believed caused primarily by devitalization of a band of cells girdling the stem of the plant and in particular the cambium cell layers are devitalized by being elevated in temperature by dielectric heating or induction heating effects.