I have a small hornbeam tree, Carpinus japonica, roughly 6 feet tall. It has never been pruned and was just transplanted to a small shade garden, close to a path. It will need to be pruned to keep the canopy high. Should this tree be pruned lightly? Is it at a good age or time to prune and to make a single trunk tree? Would fall be the best time to prune?
According to the American Horticultural Society’s Pruning & Training (edited by Christopher Brickell, DK Publishing 2011), Carpinus species tolerate pruning well, but it is best to do it from late summer to midwinter, to avoid severe bleeding of sap. Your tree is quite small, and it should be fine to do light pruning and remove any branches that are going to interfere with the path. (Heavy pruning can result in twiggy growth.) It’s not uncommon to prune it to a central leader standard (more upright form).