The student is over-controlling with a vice-like grip on the stick. The instructor does appear to reduce power after the very late GA, then re-apply it when he sees the trees looming up. The aeroplane never seems to be recovered from the high alpha of the landing flare, and there is no deliberate left turn. In fact as the bottom drops out of it and the aeroplane stalls and rolls off to the left the student lets go of his stick, and the instructor appears to grab his own stick and pull it hard back!