It is said that the sole difference between a bad haircut and a good haircut is just two weeks, but this maxim does not apply to drastic pruning of maple trees (Acer spp.) . “Topping” a tree is much more like decapitation than the cosmetic process, causing severe pruning wounds and destroying the maple’s natural form. If you own a maple whose top branches scrape on an electric line, you may use crown reduction pruning to reduce the tree’s height.
Prune your maple at the late fall while it’s dormant. Even though the tree is without leaves, it’s easier to see its structure, and dormancy prevents excess sap flow from the pruning wounds. Use hand pruners for divisions with diameters of under 1 inch, lopping shears for diameters around 2 3/4 ins, and pruning saws for those that are larger. For branches from reach, use a pole pruner.
Prune for security first, removing dead and dying branches at the point at which they connect into the back. Prune out diseased or broken branches at least 6 inches into wood. Make each cut just over a lateral branch that’s at least 1/3 the diameter of the cut stem. Take out among two spanning branches to prevent rubbing wounds.
Walk around the maple and then determine how many ins have to be removed from the top of its crown. Cut each of the highest branches just above a lateral branch at least 1/3 the diameter of the division to be cut. Select lateral branches with powerful, U-shaped angles of attachment into the tree rather than narrow angles of link.
Limit pruning into a maximum of one-quarter of the maple’s canopy at any 1 year. If more pruning is needed, save it until the following calendar year.