roots
With Japanese Maples I don't see much of a problem due to the fibrous nature of the roots of this species. With Ginkgo biloba and others there is more concern. Whenever repotting I will root prune or "slash" the rootball if needed. I have been using some root control containers, looking for the cost effective "magic bullet". Air pruning pots, fabric root control grow bags, fiber pots, mesh grow bags in cinder blocks and copper treated containers. Timely shifting up the plants and eventually planting the material in the field would work. Some containers I am trying are "Smart Pots" by Root Control, Inc., "Root Trapper" by RootMaker Products Co. LLC, "Accelerator" pots, a "Florida Cool Ring", some fiber containers by Western Pulp Products Co., fiber pots incorporating copper by Henry Molded Products, Inc. and Tex-R Agroliners by Texel which is a copper lined insert used in bag-in-pot production. I use them above ground currently but may sink a few below someday. They suggest inground containers utilizing the Agroliner. If you can still get Spin Out you can paint the insides of your containers. I think you can buy containers with that product incorporated in the molding process from Nursery Supplies, Inc.. There is a liner nursery in TX, Rennerwood, that uses RootMaker containers and they do a great job. Cherry Lake Nursery is another that uses a variety of root control technologies including the Air-Pot. For more info I suggest doing a Google Search on the subject, check out info available at the SNA website and/or contact professor John M. Ruter of the University of Georgia.