Despite all of the beauty and environmental benefits trees provide, it’s important to recognize the fact that they can also present safety risks at times. Trees can fall on homes, cars, or landscaping, while branches can sometimes drop suddenly, endangering people, pets, and property in the vicinity.
So, sensible tree management is necessary to maximize the value of landscape trees while minimizing the risks they may present. The trick is learning to spot the signs that indicate a tree may be hazardous. That way, you can contact an ISA-certified arborist and have your tree professionally assessed.
We’ll share a few of the most common and concerning signs that indicate a tree may be hazardous below.
Hazardous Trees: Target Required
Note that a target is necessary for a tree to be considered hazardous. Even a dead tree that’s falling apart and already leaning over isn’t hazardous if it’s located in the middle of an abandoned wood lot. Only trees that may cause harm to people, pets, property, or other high-value targets can — by definition — be considered hazardous.
11 Signs That a Tree May Be Hazardous
It’s important to understand that trees are complex living organisms, meaning that it can be difficult for homeowners to determine which signs actually indicate a hazardous condition that requires pruning or removal and which ones only require monitoring.
So, while you’ll want to inspect your trees regularly and consult with a professional arborist if you see any of the following signs, none necessarily indicate that mitigation is required.
1. Cavities or Hollows
Tree cavities certainly provide value to the local wildlife, and they can even be aesthetically pleasing in some cases. But they can also be associated with extensive internal decay that may compromise the structural integrity of the trunk or large branches.
2. Large Dead Branches in the Canopy
Most large shade trees will have a few small dead branches here or there, which rarely present a serious safety risk. But large dead branches can be surprisingly heavy, presenting obvious safety concerns as fungi and other microorganisms begin breaking down the wood fibers.
3. Soil Cracks or Heaving
Soil disturbances often indicate that the root system, the soil, or both are losing their structural integrity. This can predispose a tree to windthrow in severe weather or even, at times, failure during calm conditions, making this a serious sign that demands immediate attention from an ISA-certified arborist.
4. An Increasing or Sudden Lean
Many trees develop a moderate lean gradually as they grow, and a longstanding lean does not necessarily indicate instability. But trees that begin leaning suddenly or leaning more than usual may be suffering from problems in the root-soil plate, putting them at risk of collapse.
5. A History of Limb Drop
Unfortunately, trees that have shed large limbs in the past are often at greater risk of dropping large limbs in the future. This can occur for a variety of reasons, ranging from pest problems to disease to fungal activity. In any case, it is wise to have these trees assessed as soon as possible.
6. Mushrooms or Conks
Mushrooms or conks growing from the stem, branches, or roots are often a sign of fungal activity within a tree. Different fungal species present differing threat levels, but it is always worth having them inspected by a certified arborist, who can determine the likelihood that they’ll compromise the tree’s structure.
7. Weak Branch Unions
While strong branch unions can be quite resilient, weak junctions may fail suddenly. Tight, V-shaped branch junctions, for example, may contain included bark that prevents proper branch attachment, while epicormic shoots (“water sprouts”) are often weakly attached to the parent branch or stem.
8. Cracks in the Wood
Cracks or splits not only indicate a heightened risk for future failure, but they actually indicate that the wood is already failing. While any significant crack is cause for concern, those that occur in the horizontal plane (across the branch’s axis) or flex when the wind blows are especially serious.
9. Root Damage or Decay
Your tree’s roots help anchor the tree and keep it stable. So, it’s always important to take root issues seriously. Major structural roots that are cracked, split, severed, or have hollows should be examined by an ISA-certified arborist, particularly if they’re located relatively close to the trunk.
10. Crown Dieback
The progressive death of branches within the crown is often a sign that the tree is suffering from environmental stress, pests, disease, or some other factor. Not all of these issues will affect the structural integrity of the tree, but because some can, it’s wise to have the tree examined.
11. Large Areas of Missing Bark
Large areas of missing bark are important clues that often go overlooked by homeowners. Unfortunately, when large sections of bark slough off a tree (or can be removed easily), it generally indicates that the cambium layer has died, which may be a sign of significant health or structural problems.
Tree Health & Tree Stability Are Two Different Things
Many homeowners are surprised to learn that a vigorous, healthy tree may be at risk of failure, or that a tree battling a serious pest or disease problem is actually not presenting a serious safety hazard. That’s because tree health and structural stability are different (though sometimes related) factors.
Hazardous Tree Signs North Carolina Homeowners Should Know: FAQ
Don’t worry if you still have questions about the signs hazardous trees can present — many homeowners do. To help, we’ll answer a few of the most common questions our clients have below.
Can a healthy tree still be dangerous?
Absolutely. Even trees that are growing rapidly and possess full canopies can still be hazardous if they have poor branch structures, internal decay, or compromised root systems.
Does a hollow tree need to be removed?
Potentially. While some trees remain stable despite large hollow sections, others may have lost their structural integrity and be at risk of failure. That’s why it is important to have trees with hollows assessed by an ISA-certified arborist.
Is a leaning tree always dangerous?
No. Some trees develop a natural lean over many years, while producing sufficient response growth to accommodate the lean. However, trees that begin leaning suddenly or start leaning more than usual may be at risk of failure.
Can a dangerous tree be saved, or does it need to be removed?
In some cases, trees exhibiting troubling signs can be saved via weight-reduction pruning, cabling and bracing systems, or other corrective actions. However, other trees may, in fact, require removal to restore safety to your property.
How often should I inspect the trees on my property for hazards?
There’s no single tree-inspection time frame that’s appropriate for all situations. That’s part of the reason homeowners should learn to recognize some of the signs that may indicate a hazardous condition. However, for maximum safety, you may want to consider having your trees inspected annually.
Should I have my trees inspected after a major storm?
Yes. Storms often cause damage that may not be immediately visible to homeowners. But certified arborists have the training and experience to spot the subtle signs indicating a tree may require corrective action.
When possible, it’s also wise to have trees inspected before a major storm system rolls through. That can help you address problems proactively and potentially avoid the need for an emergency tree removal.
Are some tree species more likely to fail than others?
Yes. Some species have growth habits, wood characteristics, or branch structures that can make them more prone to breakage. Fast-growing, weak-wooded species, such as black willows (Salix nigra) and silver maples (Acer saccharinum), are good examples.
With that said, trees of any species may fail, so it’s always important to watch for signs of a potential hazard.
Don’t Ignore the Signs That Your Tree May Be Hazardous
Remember, these signs don’t necessarily indicate your tree needs immediate corrective action, but that doesn’t mean you can afford to ignore them either. It’s always better to err on the side of caution rather than leaving your home or family at potential risk.
The Lubbers & Sons Tree Care team would be happy to assess your trees and recommend the best path forward. Contact us today to schedule a free onsite evaluation and enjoy the peace of mind you deserve.
Sources and References
- USDA Forest Service – “Hazard Trees”
Federal guidance on recognizing hazard trees on public lands, covering the warning signs — dead limbs, cracks, lean, root damage — that indicate a tree may fail and pose a safety risk.
https://www.fs.usda.gov/visit/know-before-you-go/hazard-trees - NC State Extension – “How to Spot Sick or Stressed Trees”
Extension article on identifying early indicators of tree stress and decline, including canopy dieback, discolored foliage, and bark or trunk abnormalities, so problems can be addressed before failure.
https://homegrown.extension.ncsu.edu/2020/07/23/how-to-spot-sick-or-stressed-trees/ - North Carolina Forest Service – “Trees and Storms”
State forestry agency guidance on protecting trees from storm damage, assessing damaged trees afterward, and deciding which can be saved versus removed.
https://www.ncagr.gov/divisions/nc-forest-service/urban/trees-and-storms - Arbor Day Foundation – “Look Out! Detecting and Preventing Hazardous Trees”
Conservation nonprofit guide to spotting the structural defects and warning signs of hazardous trees and taking preventive steps to reduce the risk of failure.
https://www.arborday.org/perspectives/look-out-detecting-and-preventing-hazardous-trees - North Carolina Urban Forest Council – “NC Trees & Storms”
Guide to preparing trees for storms and evaluating storm-damaged trees, aimed at helping North Carolina property owners make sound retention-or-removal decisions.
https://www.ncufc.org/NC-Trees-Storms.php
