At least once a month, we get a request for topping someone’s trees. The reasons are myriad: The tree is blocking the view, it’s impinging on satellite service, it’s deemed too tall and hazardous, or someone just likes the look. On the surface, topping doesn’t seem like a bad idea. You get to keep your tree and have it out of your way. In reality, though, topping is a terrible practice, and we try to dissuade all our clients from having it done.
Why is topping trees so bad?
There are a lot of reasons, but first and foremost is that it will likely kill your tree. Hacking it back may not kill it this year or next, but your tree’s lifespan will definitely be shortened.
Topping drastically reduces a tree’s leaf mass, limiting the tree’s ability to produce food and sustain itself. This causes root dieback. Also, the site of an indiscriminate topping cut can provide access to decay, insects, and disease. And limbs newly exposed to sun without the protection of the canopy may become sunburned, leading to cankers and branch death. All of this leads to an unhealthy, unstable tree.
Furthermore, topping often leads to something we call “witchbrooming.” This is where a multitude of branches sprout from near the cut. These epicormic branches are weakly attached and can grow up to 20 feet in one year. Such limbs are susceptible to breakage in storms, causing more damage than the tree originally would have.
Another problem with topping is that it will ultimately cost you more in the long run. More frequent pruning will be necessary to mitigate branch failure risks and to rein in the height of the new epicormic branches. Furthermore, as the tree’s health declines, it may just have to be removed after a number of years.
Finally, topped trees are ugly. When you consider that healthy, well-maintained trees can add 10-20 percent to the value of your property – and topped trees can be seen as a safety risk – why would any homeowner request the practice?
What’s a homeowner to do instead?
However, there are healthy approaches to canopy reduction. One method is called “drop-crotching,” where tall limbs are cut back to an appropriate branch that can take on a terminal role. This branch must be at least one-third the size of the one removed. Drop-crotching can diminish height while maintaining the shape and health of a tree. However, this is only appropriate for trees with a rounded, or decurrent, shape. Pyramidal, or excurrent, trees (think conifers) simply cannot have their height reduced without negative consequences.
In some cases, the best practice is to remove the problem tree and replace it with one better suited to the site.
If you are considering topping your tree, please give us a call. We can offer alternative approaches that may solve the problem at hand.
For more information, read “The Myth of Tree Topping,” from PlantAmnesty, “Why Topping Hurts Trees,” from the International Society for Arboriculture, or “What’s Wrong with Topping Trees?” from Purdue University.