THE PILOT WAS ATTEMPTING A LANDING ON THE SHORT RUNWAY. HE STATED THAT HE USED 85 KNOTS INDICATED AIRSPEED ON FINAL APPROACH. THE AIRPLANE FLOATED DOWN THE RUNWAY, AND DID NOT TOUCH DOWN UNTIL APPROXIMATELY ONE HALF OF THE RUNWAY HAD BEEN USED. THE AIRCRAFT RAN OFF THE END OF THE RUNWAY, AND IMPACTED TREES BEFORE COMING TO REST ON A GOLF COURSE PAST THE DEPARTURE END OF RUNWAY 31.