A GROUND WITNESS OBSERVED THE AIRPLANE CIRCLING AT A LOW ALTITUDE OVER HIS PROPERTY. THE AIRPLANE THEN STRUCK A 100-FOOT TALL FIR TREE AND IMPACTED TERRAIN. BRANCHES FROM THE TREE WERE CUT BY THE PROPELLER AND FOUND ALONG THE WRECKAGE PATH. NO EVIDENCE OF PRE-IMPACT MECHANICAL DEFICIENCIES WAS FOUND. THE GROUND WITNESS WAS AN ACQUAINTANCE OF THE PILOT AND STATED THAT THE PILOT HAD FLOWN OVER HIS PROPERTY ON PREVIOUS OCCASIONS. THE PILOT HAD RECEIVED HIS PRIVATE PILOT CERTIFICATE LESS THAN THREE MONTHS PRIOR TO THE ACCIDENT.