The pilot stated that at about 70 feet agl on climb after take-off, the aircraft encountered turbulence. As he was applying left aileron to counter the turbulence, the engine suddenly stopped. The pilot checked the position of the fuel selector and turned the aircraft towards a cleared area. The aircraft was landed in a timbered area about 550 metres beyond the end of the strip. When the aircraft came to a stop the pilot noticed that the ignition switch was in the off position. The pilot was wearing a loose sleeved pullover during the flight and it is thought that whilst countering turbulence the cuff caught the ignition switch and pulled it to the off position.