Fruit-Tree Trained Upright as an Espalier
Espalier is the term applied to a mode of training fruit trees in the open ground. For a single tree a row of stakes about five feet high driven into the ground, about nine inches apart is the start. Then a narrow strip of wood is laid on the tops of the stakes and a nail is driven into each to hold it firmly.
GalleriesTree Trimming and Removal
Nicholson, George The Illustrated Dictionary of Gardening, Div. VI (London, England: L. Upcott Gill, 1884)