When a tree needs topping, it really needs to be removed and replaced with a tree whose mature size will be appropriate for the space. Your local Cooperative Extension Service or county forester can help you make a good choice.
Topping trees (removing a major portion of the top growth to reduce the size of large trees) severely damages trees and creates more work for the homeowner. Plants establish a balance between the above and below ground parts. The above ground portion is usually only about 60 percent of the plant and is primarily responsible for photosynthesis, which 'feeds' the plant. The underground portion of the plant (roots) is responsible for the uptake of water and nutrients necessary for the plant to function.
Removing a major portion of the plant top causes multiple new shoots to form as the plant strives to restore the balance between roots and vegetative plant parts. These new shoots result from fast-growing, weak wood, laden with leaf tissue and vulnerable to breakage and wind damage. If the tree survives, it is usually just a few years before it once again outgrows its space. For more information on hazards if topping, read: Topping—Tree Care or Tree Abuse?.
