The automated irrigation system for trees includes a capacitance sensor having a pair of probe plates configured for clamping a trunk of a tree therebetween. The capacitance sensor is configured to measure a capacitance of a portion of the trunk of the tree between the pair of probe plates. A water reservoir stores water for irrigation, and a pump is in fluid communication with the water reservoir for selectively pumping the water therefrom. A conduit is in fluid communication with the pump for carrying the water pumped by the pump to soil around the tree. A controller is in communication with the capacitance sensor and the pump. The controller is configured to calculate a relative permittivity of the portion of the trunk of the tree and to actuate the pump to deliver water to the soil around the tree when the relative permittivity falls below a predetermined threshold.