Topping is not a viable means of tree management for size or risks. In fact, topping renders the tree a greater hazard over time.
Topping stresses trees by removing between 50-100% of the leaf-bearing crown, where trees manufacture much of their food. The now-starving tree will quickly produce thin shoots around the cut to quickly generate leaves for nutrition. These fragile shoots are prone to breakage; they grow abnormally and never fully anchor to their parent branches. They may become projectiles in wind and storms.
Topping leaves a compromised tree more susceptible to insect and disease infestations.
Topping promotes tree decay by creating wounds the tree is unable to close over.
Topping reduces the crown cover, and exposes underlying leaves to high levels of light and heat and can sunburn the tissues beneath the bark.
Topping strips the tree of many of its beneficial effects, such as carbon sequestration, oxygen and water filtering, suitability in the biohabitat and the increase to property values (averaging 5-15%) from healthy, attractive treescapes.