WITNESSES IN THE AREA OBSERVED THE VEHICLE FLYING IN THE LOCAL AREA AT OTHER TIMES HOWEVER THIS WAS THE FIRST TIME THEY HAD SEEN TWO PEOPLE IN IT. THEY ALSO OBSERVED THE VEHICLE FLYING ERRATICALLY AFTER LIFTOFF AND NOTED THAT THE WINDS WERE GUSTY. UPON RETURNING FOR LANDING THE VEHICLE WAS NOTED TO DESCEND OVER A SET OF HIGH TENSION WIRES INTO A SLOPING GRASS COVERED FIELD ABOUT 600 FEET LONG WHICH ROSE AT THE OPPOSITE END. IT WAS THEN OBSERVED TO ATTEMPT TO CLIMB UP ABOVE THE RISING TERRAIN AND COLLIDE WITH A TREE ABOUT 30 FEET HIGH LOCATED NEXT TO THE LEFT REAR CORNER OF A HOUSE. THE OWNER OF THE RESIDENCE OBSERVED AND HEARD THE ENGINE RUN A A CONSTANT PITCH UP UNTIL IMPACT WITH THE TREE. THE STUDENT-PILOT HAD BEEN WARNED BY PERSONNEL REPRESENTING THE COMPANY WHO HE HAD PURCHASED THE MXL II FROM THAT THE ABOVE MENTIONED FIELD WAS UNSAFE TO FLY OUT OF.