Good question. The central pole acts like a kind of skewer. It keeps the hay from sliding off the top and falling over. As to the height of it, having someth

Good question. The central pole acts like a kind of skewer. It keeps the hay from sliding off the top and falling over. As to the height of it, having something to keep your balance on top of the stack is essential. One of the photos shows the person standing on the stack and their head is at about the same height as the pole.