This project has since been relocated
In 1991, I planted 11 short Elm tree "whips" in a row up a hill. I began bending and tying them to a frame. Eventually they were grafted, one to the next, going uphill. Finally there will be one long uphill trunk supported by 11 trees, basically one tree with 11 trunks feeding it.
One interesting phenomena of multiple grafting to a trunk is that the trunk actually enlarges as it goes up! This is contrary to all our learned visual assumptions we are used to, of a gentle taper to a trunk.