This is such good practice and i have often thought the technique works on smaller younger trees if they have to be reduced or maintained at a height below that of what their natural form would take.
Trees that have stood the test of time and show some battle scars, dead branches, and other signs of aging are often referred to as veterans. On a once-beautiful tree, these signs might suggest a ‘mortality spiral’ to tree owners, and to arborists. ‘Death with dignity’ may seem simpler than dealing with maintenance and liability concerns, but with proper standards to follow, veteran tree care methods are straightforward and defendable. The British have been at this for a long time. Their tree care standard describes a natural process of pruning veteran trees:
“Retrenchment pruning is a phased form of crown reduction, which is intended to emulate the natural process whereby the crown of a declining tree retains its overall biomechanical integrity by becoming smaller through the progressive shedding of small branches and the development of the lower crown (retrenchment). This natural loss of branches of poor vitality improves the
ratio between dynamic (biologically active) and static (inactive) mass, thus helping the tree as a whole to retain good physiological function...The pruning should be implemented by shortening heavy, long or weakened branches throughout the crown, while retaining as much leaf area as possible and encouraging the development of new secondary branches from epicormic shoots or from dormant or adventitious buds.”