The airplane experienced a total loss of engine power during an enroute climb to cruise. The pilot performed a forced landing to a field where the airplane struck trees and sustained substantial damage. The pilot stated that he forgot to add engine oil during an oil change he performed on the airplane before the accident flight. He said he forgot to add the oil because he was rushed and had personal activities to perform. Examination of the airplane confirmed engine oil starvation. Postaccident examination of the airplane revealed no other mechanical anomalies that would have precluded airplane operation. The pilot held a private pilot certificate and a mechanic certificate with airframe and powerplant ratings.