The pilot had undertaken a private flight from Port Pirie intending to land at a property. When he arrived in the general area, he saw an airstrip with a vehicle parked nearby and believing that he had arrived at his destination commenced an approach for landing. After the aircraft had touched down the pilot realised the airstrip was not suitable for the operation, but was committed to continue with the landing. The aircraft over-ran the end of the airstrip with the left wing striking a tree causing damage to the wingtip and displacing the spar rearwards. The pilot being the only occupant was uninjured.