One practice of pruning that is frequently overlooked is structural pruning of young trees. Trees in forests grow straight and lose lower branches due to competition for light. When planted in full sun many species develop multiple trunks that are more prone to failure. Lower branches tend to grow at the same rate as the leader that results in weak attachments. Training trees when young and growing quickly is crucial to establishing a strong framework for future growth.  The focus is on pruning to a single dominant leader with branches pruned so their size is proportional to the stem diameter. Branches are removed to ensure adequate spacing between limbs so the shape of the tree is maintained to a natural open grown shape.
A soil-applied growth regulator can control growth up to 90%. As plants grow more slowly they direct more energy into defense, root and storage systems. Greater tolerance of heat, drought, pollution insect and disease problems over untreated trees are well documented. Regularly pruned plants,  near pools, patios, houses etc., blocked scenic views, construction damaged, declining and stressed and large trees in limited spaces are all uses for growth regulators. One treatment usually lasts for 3 years.
The Emerald Ash Borer  will kill every ash not protected and the Treeage injection by Arborjet is the only product to give two year protection with one application. All treatments are done by an ISA certified arborist. The cost of treatment is usually less than removal and replacement.