Thinking of topping your trees? Think again…
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.
These Norway spruce trees will be unable to heal over the wounds that topping created, thus leading to rot and structurally unsound trees.
Why is topping 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.
It’s no surprise that such extensive topping killed this tree. If you want to cut a tree back that much, it’s better to just remove it entirely.
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?
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.
Cankers are often quite visible, but cause and treatment aren’t always straightforward…
Cankers tend to be prominent. If your tree has a potentially hazardous canker, it’s hard to miss. Think of the tree version of a large, open wound or deformity, and you’ve got the visual idea of cankers. They may be ugly, but are they a problem? Maybe yes, maybe no. And maybe not quite yet.
An older callused canker on a paper birch. Photo courtesy Markus Hagenlocher via Wikimedia Commons.
Visually speaking, cankers are places on the trunk or branch of a tree where the bark is sunken or missing. They can lead to hazardous situations, creating weak spots where breakage can occur. Of most concern are cankers that affect more than 120 degrees of the tree’s circumference or cankers connected to other tree defects (e.g., cracks, weak branch unions, or cavities). Also of concern are cankers that are either directly facing or opposing prevailing winds.
Note the callus formed on the canker on this spruce tree. Photo courtesy Сыроежкин via Wikimedia Commons.
Cankers are typically caused by bark-inhabiting pathogens (usually fungal or bacterial), but sunscald and frost can also cause cankers by killing patches of bark. And while a wound on a tree (an improperly cut branch or a damaged place on the trunk) won’t directly lead to a canker, it can be the entry point for pathogens that will.
Cankers can either be annual or perennial. The annual ones are handled in a single year by a healthy tree, which grows a callus over the affected area. A perennial canker returns year after year, growing slightly bigger in the process. The pathogens attack the callus each year, meaning the tree has to start over again. These cankers often have the look of a target on the face of a tree, exhibiting concentric circles. Though these cankers may be visually unappealing, they are slow-growing, and you may be able to enjoy your affected tree for years to come.
What you really need to be concerned about is canker rot. This is when the canker is actually associated with fungi that is decaying wood inside the trunk of the tree. Thus, you have the combined issue of poor internal structure (from the rot inside the tree) and dead bark and tissues on the outside of the tree. Trees exhibiting canker rot are very hazardous and should be dealt with immediately.
Cankers come in all shapes, sizes, and can be from scores of different pathogens. Often, we can’t pinpoint how exactly the canker came about, but we can assess your tree and let you know if the canker is simply an eyesore or a true hazard.
For more information on cankers, the Forest and Shade Tree Pathology website is absolutely the best place to go…and it will make your head spin with all the scientific information they have to share. For an overview, go to their Cankers page, and to learn about specific diseases, go to Cankers on Parade.
How to tell if the tree looming over your house and in your thoughts is a hazard tree…
Let us help you determine if your tree is a hazard before it does this.
It’s big and it’s heavy, and it’s got the potential to put a major dent in your home and your finances…but is it truly a hazard tree? When should you worry? And when should you simply be grateful for the extra shade?
We at Sand Creek Tree Service are experienced in assessing hazard trees. That said, not all problem trees are readily detected. Sometimes the structural defects are hidden inside the tree or below the soil. Sometimes, a “better safe than sorry” approach is best. We’ll always discuss options with you, letting you make the final call when it comes to potential risks that are hard to quantify.
However, many hazard trees present signs of their structural weaknesses. Ultimately, a hazard tree is one in which the weight of a tree – or a part of the tree – exceeds the tree’s structural integrity (in a branch, trunk or roots). When assessing your tree for risks, we evaluate the likelihood of the tree failing, the environment that contributes to failure, and the target (the part of your property that would sustain damage).
There are seven general problems that point to your tree being a hazard tree: decayed wood, cracks, root problems, weak branch unions, cankers, poor tree structure, and dead portions of the tree. Decayed or rotting wood is often indicated by shelf mushrooms – a parasitic fungus – growing on the trunk. Cracks are often obvious and can be the result of lightning, frost, or other factors. Root problems might be evidenced by a bulging in the ground to one side of the tree, indicating that anchor roots are slowly losing their capacity to hold the tree in place. Weak branch unions can appear as a kind of seam in the bark, a sign of included bark. This means the branch is not fully connected to the rest of the tree; as the limb grows over the years and increases in weight, that union my fail. Cankers will look like a bulge or deformation in the trunk of your tree, meaning that the bark and cambium layer are dead and nutrients aren’t flowing through the tree as they should. Poor tree structure simply implies that your tree has grown in a direction or manner that makes breakage more likely. Perhaps the tree has a heavy lean, or maybe a horizontal branch has acquired too much weight. Finally, a hazard tree is most obvious when it is dying (dead top or branches) or completely dead.
Besides looking at these seven factors, we also assess the direction of prevailing winds in your area and which direction your hazard tree might fall. Another important factor to consider is the target. What will the tree damage when it falls? If you have a hazard tree without the potential to damage your property or injure anybody, we sometimes suggest letting nature takes its course. Trees that humans deem hazardous can make for important animal habitat. Think of all our local eagles and osprey that nest in snags.
If a potential hazard tree is regularly invading your thoughts, don’t hesitate to give us a call. It’s better to bring down a tree in a controlled manner – especially around people and structures – than to let your roof bear the brunt. And who knows – maybe your tree is perfectly healthy and willing to provide you and your family shade and birdsong for another fifty years. But a little peace of mind provided by a professional is always worth the effort.