Childs Rocking Chair

This little chair was on the way to the pit just like the sewing box, but I'm hoping to give it new life. It looks really old, but the seat is made from plywood. So my first question is when did they start using plywood?
Next, does anyone know if this chair originally had a hardwood seat, and was it just fixed with the plywood? Is it primitive or is there a style to this chair?

Was found in Kingston NB Canada.