This was the student's first session on practice forced landings. The instructor demonstrated a forced landing approach, and then positioned the aircraft for the student to practice an approach. The instructor intended to demonstrate to the student the dangers of trying to stretch the glide. The approach was flown by the student into wind with full flaps set, descending to a low height with the speed reducing to 55 knots. The student failed to respond to the instructor's call to watch the airspeed. The instructor took control, applying full power, but too late to avert the descent. The aircraft port wing tip contacted a bush and the resulted ground contact caused the nose gear to collapsed. The instructor estimated the wind as from the north-west at 15-20 knots and thought there was probably wind shear at low level, which contributed to causing the ground contact.