Abstract: An apparatus for injecting fluid under pressure into trees having a base and a plurality of cylinders supported by the base for receiving injection fluid. Each cylinder has a first end, a piston reciprocable in the cylinder for injecting fluid from the cylinder into a tree, an opening when the piston is moved to a position away from the first end of the cylinder, and an independent injector. Each cylinder also includes an actuator connected to the piston for moving the piston toward and away from the first end, and having an adjustor for selecting the amount of fluid to be injected. First and second conduits are connected to the first end of the cylinders. The first conduits are in communication with a reservoir of injection fluid and the second conduits are in communication with the injectors. A plurality of third conduits are also included, and are in communication with the cylinders when the piston is moved to a location away from the first end. The third conduits are in communication with the reservoir.