Trees in Earth Boxes

Last weekend Jennie and I attended an all-day workshop on 'edible landscaping' at Raintree Gardens in Morton, Washington. Our teacher, Bruce Weiskotten, gave me a new idea. Then I remembered that I had heard of something like this 25 years ago in Holland. Trees in containers. After the workshop I bought a columnar apple tree on ultra-dwarf rootstock to plant in an Earth Box. I'll attach pictures here when I have planted it. It should get about 8 ft tall and the idea is to prune all side branches to 2-3 inches to keep it growing straight and tall. I figure one tree per 18 gal. box. Bruce said that orchardists in California are planting columnar fruit trees in fields and I remember Bob Sestrap at Wax Orchards talking about how that was being done in Holland 25 years ago. Hmmm... I wonder if apples could be harvested commercially with a machine like a corn picker.