“Please top these trees for me — they are getting too tall,” is a request that everyone from landscapers to tree commissioners has heard repeatedly.
No responsible tree manager ever “tops” trees, so the response to the request usually contains another question — “Can you explain what you mean by ‘they’re getting too tall?’”
At this point, the tree owner will have one of two responses. First, he or she might say, “When we planted these trees, they were just little twigs that we brought out of the woods and put in the ground. Now look at them, you can’t even see our house.” Or, the tree owner will say, “If they fall on the house, we will be killed. They are just too tall.”
The first case is common. The homeowners put the wrong tree in the wrong place. In contrast, it is easy to put the right tree in the right place. Homeowners should decide before planting what height and spread the space they are planting in will allow. Then they should plant a tree that will mature at that size.
But for now, topping will not help the situation. Instead, the injured trees will just push more growth toward that mature size for which they are genetically programmed. Maintenance and risk will be increased, the trees will be ugly and the house will be blocked again shortly.
Topping these trees is not a legitimate option. If the tree owner does not want these trees removed, they still have options. They can choose a “crown-raising,” in which the lower branches are removed, a “crown-thinning,” in which some of the crown is removed allowing for increased penetration of air and light, or a “crown reduction,” in which the size of the tree is reduced by cutting primary limbs back to secondary limbs.
In every one of these pruning options, the tree owner will often be surprised that his or her goals are achieved without topping or removal. However, removal and replacement may also be an option. An example of this replacement might be removing a series of maples and replacing them with much smaller flowering hawthorns.
The second case is also common. Here, the tree owner needs to realize that risk is not directly connected to height of the tree. Among other things, risk is related to likelihood of failure. In many cases, topping trees actually increases the likelihood of failure. In other cases, if there is an existing likelihood of failure, other methods of abating that risk are more successful than topping. For example, if there is a weak branch attachment, topping those branches will soon actually make the branches more top heavy, thereby increasing the likelihood that the tree will split and cause damage.
In the case of perceived risk, the tree owner should ask for a tree risk evaluation and risk abatement rather than topping.
Joshua Arp is an ISA-certified Municipal Specialist, a Clarks Summit Tree Commissioner and an operator of a landscape maintenance business. He can be reached at firstname.lastname@example.org.