I'll spare you any long, drawn-out suspense and just tell you. The worst tree care practice is “Topping” .
“Topping is perhaps the most harmful tree pruning practice known. Yet despite more than 25 years of literature and seminars explaining its harmful effects, topping remains a common practice.” This is the opening paragraph of a brochure put out by the International Society of Arboriculture (ISA) on why topping hurts trees. The Tree Care Industry Association and every university research department in Arboriculture have agreed for decades that topping is bad, very bad.
Despite being ugly, or regardless of any degree of artistry applied to topping, it still has many detrimental effects to the tree both short and long term.
If you have ever seen a topped tree, the cuts on the top of this tree range from 4”-12” in diameter. Cuts of this size cannot possibly heal before decay will start to rot through all the main leaders of the tree. Once this process starts, there is no way to stop it. This particular tree is a Silver Maple. It will sprout back out; however, the new growth is basically sucker growth. These limbs are poorly attached to the tree and are more prone to breaking. The new growth also grows twice as fast and twice as thick as the original limbs. Don't forget, the new shoots are growing from a leader that is beginning to rot. In the case of many hardwood trees (oak, ash, hickory, American elm) a severe topping can sometimes kill the tree due to the much slower growth rate among hardwoods. The leaves are the food factories for the tree, and the removal of a major portion of them stresses the tree.
From a maintenance stand point, topping is also more expensive. As I talk to people requesting topping, the number one reason I hear is “The tree is getting too tall.” Using this logic, and remembering the “twice as fast and twice as thick” growth, you end up having to top again in a few short years. Also, removing a third to a half of a tree's crown produces more debris to clean up, which results in a higher price.
Is topping a tree ever acceptable? Yes. If the only other safe alternative were the removal of the tree, such as in the case of severe storm damage, then topping would be better than losing the tree. If someone recommend topping to you in any other circumstance but this, seek your tree care services somewhere else.
Most people top their trees because they don't know the damaging effects, and that there is a better alternative. Nearly all of the people I talk to regarding topping change their minds and opt for proper pruning instead. This is certainly encouraging. I do hope this article will serve as a warning to all who read this. If you value your trees, do not top them. Next month we'll talk about what you should be doing for your trees. Pruning.
Russell Hodge is a Certified Arborist and can be reached by e-mail at email@example.com.