Wikipedia describes Pooktre / Tree Shaping as the following:
"Tree shaping (also known as Pooktre, arborsculpture, tree training, and by several other alternative names) is the practice of training living trees and other woody plants into artistic shapes and useful structures. There are a few different methods of achieving a shaped tree, which share a common heritage with other artistic horticultural and agricultural practices, such as pleaching, bonsai, espalier, and topiary, and employing some similar techniques. Most artists use grafting to deliberately induce the inosculation of living trunks, branches, and roots, into artistic designs or functional structures. To achieve these art forms, many different tree species have been used, but some trees are better suited than others."
