Grow a walnut tree

When I was little, we lived in the country. There was a pub a short way up the road, and there grew a huge walnut tree. It was a proper tree: lollypop silhouette, trunk that you could hug, and when I stood underneath the world seemed to revolve in the canopy.
I love walnut trees. Nuts. Big, strong trees. Huge, climbable branches. I want to own a big field and grow three in one corner, then sit beneath them in my very old age.