Tree Topping

Discussion of: Tree Condition Associated With Topping in Southern Illinois Communities
By Dean A. Karlovich, John W. Groninger, and David D. Close
Journal of Arboriculture 26(2): March 2000

Written by Shannon Rizzo

Most people like trees in their yard—I don’t think there’s any question of that. Whether it be for shade, privacy, aesthetics or energy savings, urban trees provide a lot of benefits, especially when close to the home. But there seems to be a psychological tipping point in the human brain in relation to tree height where their vegetation goes from ‘benevolent’ to ‘looming menace that will crush my house and car and children’.

I’m exaggerating a little, of course, but many people really do get nervous when large (especially old) trees are growing within crushing distance of their home, and a too-common response to this problem is to call up the local tree care company and get them to take their tree down a notch or two…which can present problems of its own.

As explored in this paper, topping (defined as ‘the drastic removal of large branches with little regard for the location of the pruning cut’) is prevalent in Illinois communities, and is slipping by as ‘just another necessary practice’ to manage tree crown size. The study compared the health of 5,252 street trees in 4 different Illinois communities, topped and untopped. Coming as no surprise to someone who knows trees, the topped trees were, without a doubt, less healthy.

I must stress the distinction between topping and pruning. I have absolutely no problem with pruning—done properly, it is a vital tool with regards to tree care, especially in urban areas where there are things like street clearance, utility lines and yes, property damage to worry about. But only when done properly.

Many people seem to follow the sort-of-logical thought pattern of ‘if I cut more limbs off, then there’s less tree to fall on my house’, not realizing that haphazard branch removal will really lead to less tree that is more likely to fall on your house. Topped trees in the study were 40% more likely to have dead branches, 77% more likely to develop insect or disease issues, 143% more likely to have large cavities, and a whopping 192% more likely to be classified as ‘in poor condition’ in general. That’s a lot of numbers, but it doesn’t take a math genius to see that there’s some correlation between topping and subsequent structural failure. Topped trees also have a tendency to develop epicormic—or weakly attached—branches growing from the wounded area. These sprouts aren’t attached to the center of the branch they originate from, but rather grow on top, and will likely snap off in the first windstorm that comes along…hopefully before they get too big to do any real damage to your house, car, or any unlucky passerby. This seems like a losing situation no matter how you look at it. Why top your trees? Why take that risk? Why open them up to so many future defects and an early death?

The problem is, as stated at the very beginning of the article…people just don’t know.

An example: I was visiting my old middle school with my father, dropping off some thing or another, when my eyes were drawn to the adjacent playground field. There were ten or fifteen maples that had been there since I was a kid. I’d never really paid attention to the details before, but three years of tree science made it glaringly obvious now—every single one of them had their terminal leader (that is, the main middle branch) chopped off.
After a few moments of Natural Resources rage (screaming ‘who has done this?!’ ‘I won’t let you die in vain!’ shaking my fist at the sky, etc.) I noticed that my father wasn’t joining in the fury. He knew that they had done some pruning the previous month…and he thought they looked great. Everyone at the school thought they looked great. People in the study thought their topped trees looked great.

That really drove it home for me that a lot of people don’t actively hate their trees…they just don’t know any better. As the study shows, there are all kinds of negative impacts from improper pruning, from the diseases, cavity formation and dieback, to weak branching and premature decline of the tree. People may even have their trees topped, have the trees die later and not realized what caused it.
Most reputable tree care companies won’t top them, but if a customer doesn’t understand the science behind pruning, they may insist. There obviously needs to be better communication and education about the consequences of their actions.

The only real way that the everyday homeowner becomes familiar with responsible pruning practices is through their tree care provider. A better understanding of the way trees grow, or how to look for a hazard, or whether it is more appropriate to get a tree pruned or removed entirely, can make all the difference in maintaining a happy, healthy landscape. Simple ignorance can lead to a lot of bad decisions, and ignorance is bliss…until a tree falls on your house.