In many ways, a tree can be a great asset to a property. It provides shade, adds character, and is a potential habitat for local wildlife, and it can have sentimental value for generations to come if it is planted within the family. However, this value can depend on the tree.
Sometimes, a tree is more of a liability than an asset. Whether it is damaged and is about to wreak further havoc or it contracts an unfortunate disease, a dangerous tree can end up posing a risk to both nearby houses and local ecosystems. That’s why it’s so important to know when a tree is more trouble than it’s worth.
Outside of adding atmosphere to a spooky mountainside mansion that’s rumored to be haunted, a dead tree offers no value whatsoever to a home. According to the Canadian arborist service Tree Doctors, it doesn’t absorb water like live trees do, it doesn’t provide any shade, and it doesn’t do the environment any favors.
Indeed, a dead tree is only a disaster waiting to happen if there’s anything around it. That’s not only because parts of it could fall and hit something (or someone) but also because dead trees are carriers of plant diseases. The only option is to get rid of it.
In some cases, this is a pretty obvious problem. If the limbs of a tree are hanging by a thread after a bad storm, the chances are very good that those limbs will eventually fall. And they need to be removed before they hurt someone or damage their property.
However, Joshua Tree Experts noted that not all critical damage is so obvious. That’s why a tree inspector can examine how serious the cracks and splits in a tree’s limbs are and how likely they are to fall. This is especially true in the case of hard-to-spot upper limbs, which they examine through binoculars.
Vertical cracks in the tree’s trunk
This consideration depends a lot on the severity and persistence of the cracks. According to the New Jersey service Alpine Tree, these cracks are known as frost cracks, and while they’re definitely the most common in the winter, just a jarring transition from sunlight to clouds can sometimes make them form.
In such cases, it’s not unusual to hear a long bang, and oftentimes, the tree will close the crack when it gets warmer and grow new wood around it. That’s why these cracks shouldn’t be sealed, as trees need to remain flexible. However, if those cracks aren’t monitored and don’t close as normal, this can mean that tree pests or fungi have found a way into it, which is the beginning of the end for the tree.
It can no longer grow leaves
There are many reasons why a tree may lose their leaves. And depending on whether it had to do with trauma, disease, age, or drought, it may be able to recover when spring comes or it may not. Trees are resilient but they’re not invincible.
That’s why Michigan State University recommended waiting until the following spring before writing off a tree that lost all of its leaves to drought. But if it can’t grow any when spring comes no matter how it lost them, that tree is probably nearing its end. That’s because the lack of leaves are usually a sign that it can’t properly photosynthesize and won’t survive the next winter.
Signs of decay
When the insides of a tree are exposed, and the wood inside gets darker and weaker as time goes on, that means a tree is decaying. According to the United States Department Of Agriculture, this decay is often caused by macrofungi, such as mushrooms infiltrating plants after they’re damaged enough to show visible wounds.
And while fungicides can help trees at early stages of decay, there can eventually come a time when the decay is too advanced and the tree is near death. In such cases, removal is the only option because a decaying tree is more likely to be a hazard for everything around it as it gets weaker and starts falling apart.
It has roots growing at the surface
Although it would be hasty to say that a tree with growing surface roots should be removed immediately, it is worth noting that this is a sign of a dangerous tree. The closer to the surface a tree’s roots grow, the less secure its hold on the ground is.
According to the Virginia landscaping service Riverbend, shallow roots are usually the result of improper irrigation that doesn’t allow water to encourage growth in the tree’s deepest roots. That means that if a storm or another powerful force pushes against the tree, it’s more likely to fall over.
Excessive leaking of sap
According to the Missouri Botanical Garden, a tree that oozes significant sap from its wounds is experiencing gummosis. Although this is not a disease on its own, it’s a symptom of a larger problem that suggests a tree is in poor health or dangerous.
Unfortunately, it’s not often clear exactly what gummosis is a sign of. Since it could be anything from blunt trauma to an insect infestation to disease to a harsh environment, it’s typically best to consult an arborist when gummosis is spotted. Nonetheless, it is a sign that something is wrong with a tree.
Although it can certainly be a concern when a tree is spotted leaning over, Penn State noted that not all leans are the same and not all of them are dangerous. Some leans, called bows, are the result of external factors like snowfall. When a tree grows wood and curves upwards after a lean, this is typically called a sweep and is about as healthy as a leaning tree can get.
However, the real problem comes when a tree is as straight as an arrow and leaning over. These leans are the most likely to result in a tree falling over and indicate that the roots and soil under the tree gave away. A straight lean is especially likely if that tree’s lean gradually grows more dramatic in its angle over time.
A ring of missing bark going all around the tree
When the wood beneath the bark is as exposed as completely as it is here, there’s no hope left for the tree. According to the University of Saskatchewan, a tree cannot move water and nutrients to its branches when its inner bark is damaged. Although this is survivable in cases of minor bark loss, that’s less true when there’s a ring of exposed inner bark all around it.
This is called girding, and it’s usually done by insects and rodents who treat tree bark as a food source, especially in the winter. When a mature tree is girded, this is essentially a death sentence for it, and the best option is typically to cut it down before the tree dies and then falls over.
Excessive animal attention
In the natural world, it’s hardly uncommon for trees to receive visits from various animals. Chipmunks and squirrels will fit themselves into their knot holes, insects will find their way on them, and birds will nest in trees as needed. This is just part of almost every tree’s existence. However, take note when there are enough animals engaging with a tree at once as if they’re all staying at the same hotel.
This is especially true if they’re all or mostly insects. According to Penn State, dead trees are known to attract a small menagerie of creatures who either take refuge in the wood, eat it up, use it for mating rituals, or hunt other prey they expect to see in it. If all of this is going on, it’s not a good sign that the tree’s still living.
Although the name may sound kind of funny, a V crotch is a seriously concerning problem for a tree to have. According to New Mexico State University, this is because a point where two tree limbs grow in a V shape like this is almost guaranteed to trap bark in between them.
This is a problem because that trapped bark interferes with how securely attached these limbs are to the tree. As that attachment gets weaker, the limbs tend to split off from each other and fall, which is both bad for the tree and for everything around it. Whenever a V crotch forms, it’s best to cut off the less desirable limb before it has time to grow into an unresolvable issue.
Typically, it’s excessive to act like a whole tree needs to go when it has some dead branches. However, it’s also typically not doing that tree any favors to leave those dead branches in place. They should be removed as safely as possible. According to Progressive Tree Service, it’s not unusual for a live tree to try and spend its resources reviving a dead branch.
However, not only are those resources wasted when the branch is beyond recovery, but the dead branch’s presence can prevent the tree from healing properly in other ways. Also, if those branches die of disease or an insect infestation, they can spread both of those problems to the healthier parts of the tree.
A hollow trunk
Hollow trees are fairly common and are typically the result of an injury that causes internal decay. But while that sounds inherently worrying, Hansen’s Tree Service explained that this isn’t always the case. That’s because a healthy tree can usually spur enough new growth to keep a tree stably standing with even a hollow center.
However, that changes a lot when the tree is old or if the hole is the result of a disease. In both cases, there could be enough structural problems affecting the tree that the safest option would be to remove it entirely before it starts falling apart. Arborists are trained to spot the difference, but obviously dead trees are particularly dangerous when they’re hollow like this.
According to the Woodland Tree Service, it’s not always the death sentence it may seem when a tree gets struck by lightning. Indeed, the service goes as far as to say that trees can often be saved after they’re hit by lightning. However, this depends on a few factors.
Conditions such as the severity of the strike, the age and condition of the tree, and especially where the tree stands can influence whether a tree needs to be cut down. The last consideration is the most important as it’s too risky to keep a tree up if it’s hazardous to homes and communities around it. Trees struck by lightning are also more susceptible to insect infestations, diseases, and the effects of strong winds.
Branches that drop off without warning
According to the Van Curen Tree Service, it’s not unheard of for healthy-looking trees to suddenly lose branches or limbs during the spring and summer months. This is called sudden branch drop syndrome, and its primary cause remains unclear. Some theorize that the extra moisture in humid conditions is weakening the tree from the inside, while others suggest the affected trees had invisible internal problems.
Whatever is responsible for this problem, its onset is worth consulting an arborist about. After all, if it’s hard to explain why one limb fell off a tree, that makes it hard to determine whether more of them will do the same. An arborist can help pin down how dangerous that tree has suddenly become.
It’s in a precarious position
Although trees can certainly become dangerous if they’re at risk of falling, it’s also sometimes true that a tree’s position can make it inherently dangerous to everything around it. If it straddles property lines in a suburban area, its limbs could fall on either house next to it.
However, that’s not the only concern to be aware of. That’s because a tree in such close proximity to a home can also see its roots grow far enough to start invading that home’s plumbing, among other potential hazards.
Cracked or raised soil
If the soil surrounding a tree appears cracked or if it seems higher on one side than the other, that’s a cause for alarm. According to Riverbend, this is a sign that a tree is in danger of falling over soon.
When soil shows these cracks and extreme unevenness, it means that the tree is leaning at such a dramatic angle that its roots are starting to rip out of the ground. Once that happens, a tree should be safely removed because it’s only a matter of time before disaster strikes.
According to the University of Minnesota, there are varying degrees of leaf spot disease and the most common cases are fairly minor. Indeed, even a serious case isn’t often a precursor to removing a tree, but rather to preventing any further problems that may necessitate removal.
Although leaf spot diseases weaken trees’ ability to photosynthesize, most of them affect relatively small parts of the leaf area, which can make them largely sustainable. However, they’re a bigger concern if they cause moderate to total leaf loss in a tree for more than two years in a row. That’s because they stunt the tree’s growth and make it more prone to other diseases and pests.
Premature leaf falling
If a tree is shedding its leaves before autumn and isn’t mirroring the other trees of a similar species around it by doing this, it’s trying to tell the world something. Namely, that it’s under some pretty serious stress.
According to Bartlett Tree Experts, early leaf color changes and falling usually indicate root and soil disorders. Spotted early on, these can be remedied with fertilization, improved irrigation, and root invigoration. However, it’s also worth noting that this can also be a symptom of vascular disease or the presence of harmful boring insects.
Mushroom growth at the trunk
According to Pennington Lawn and Garden, root rot is a potentially fatal condition for any plant, but the really insidious aspect of it is how difficult it is to spot. After all, it’s not like a tree’s roots are often visible, and it’s sometimes its own problem if they are.
So instead, the most obvious sign that root rot is affecting a tree is the sudden or extreme growth of fungi like these mushrooms along the base of the trunk. As this fungus spreads, it turns roots mushy and brown, which indicates that they’ve already died. If they all look like that, the tree is effectively dead.
Decay at the bottom of a tree trunk
Generally speaking, there’s not exactly a good place for a tree to experience decay. When fungi are drawn to the moisture within a tree, they can undermine its health no matter where they show up. However, it’s particularly worrying if that decay is happening at the base of the trunk.
According to Mayer Tree Service, that’s the most common place to see it because that area remains wet the longest during humid periods. However, it’s also the most dangerous spot for decay, as it’s the most easily spread to the rest of the tree from the bottom.
There are many potential ways that branch dieback can manifest, but that’s usually what’s going on if the branches of a tree are discoloring, drying out, or wilting at the tips. It’s similar to what happens when human skin is discolored due to blood circulation being cut off, and that’s because it’s typically a sign of a tree’s vascular disease.
Of course, that’s assuming there’s no obvious damage to the tree, and it’s not experiencing a drought or flooding. According to Iowa State University, these diseases are usually caused by fungi growth that impedes the flow of water and nutrients to the affected branches. One such disease that affects a variety of tree species is called Verticillium wilt.
Roots that encircle the tree’s trunk
When trees are grown in cramped conditions, it’s not unusual for their roots to wrap around their trunks. However, Iowa State University cautioned that if this isn’t corrected at the planting stage, it spells a long, slow doom for the tree. This is because their encirclement will soon be tight enough to compress the tree’s stem and damage its vascular tissue.
Within 15 to 25 years of its planting, this problem will manifest as branch dieback and other vascular issues. Unfortunately, cutting the responsible roots only makes the problem worse once the tree is mature enough, as the tree loses an important (if problematic) part of its root system. The only winning move is not to let it happen in the first place.
If a tree is planted properly, most of its roots are likely to go unseen. But while this protects the roots in most cases, it also makes them more easily to accidentally damage down the line. And if a construction crew happens to dig or drill down into a tree’s roots, they effectively kill it in slow motion.
According to Joshua Tree Experts, it can take years or even decades for a tree to show signs that its roots have been damaged. But if it’s wilting or experiencing branch dieback with no signs of damage or disease, the most likely culprit is something that damaged the roots. And there’s sadly nothing to be done but removing the tree if this is confirmed.
“Pimples” on tree trunks and limbs
When people see growths on a tree, it’s typically in the form of either small “pimples” that appear on their leaves or giant burls that make a tree trunk look like it has an air bubble that can form in pizzas from time to time. According to Arb Tech Kansas City, neither of these are typically an indication that the tree is dealing with a potentially lethal problem.
By contrast, the growth that this gloved finger is pointing at is more subtle and potentially more worrying. It’s called a canker and it’s typically a sign that fungi have infested a previous wound at the tree’s surface. It takes an arborist to confirm a canker as such, but the options for dealing with them are usually to remove the infected area or remove the tree entirely.
D-shaped holes in bark
It’s true that all sorts of creatures can poke holes in a tree’s bark and potentially cause problems by doing so. However, if there’s a subtle crescent to these holes that makes them look like an upper case letter D, that’s a more specific cause for alarm.
According to Canada’s Invasive Species Centre, that’s because they’re a tell-tale sign of the emerald ash borer, an invasive insect species that’s responsible for the deaths of 99% of ash trees they’ve come across. This has had devastating effects throughout North America, and the odds are stacked against any tree infested by them.
It’s too close to other trees
As the A&E Tree Service explained, a whole world of problems can result when trees are planted too close together. And most of these problems have to do with competition for resources and the spread of arboreal diseases. In such cases, removing some of the trees and freeing up the rest is the second best option behind preventing the problem in the first place with proper planting.
Part of the problem is that the dense brush that forms when trees are planted too close together blocks out sunlight to each tree’s lower leaves. Those trees are also competing for the nutrients in the soil, which can make them weak and sickly. Finally, these trees aren’t experiencing proper air circulation, making the spread of disease easier.
Excessive bark shedding
As symptoms of poor tree health go, bark shedding is the one that is most subject to a case-by-case basis. After all, Michigan State University noted that shedding bark is a natural part of the maturing process for multiple tree species (including the one shown here), and in the case of the American sycamore, that process can look particularly dramatic.
However, it can also be a sign of disease or the effects of a harsh environment. In such cases, it’s typically the most useful as a warning sign when it appears in concert with other symptoms. After all, a tree that’s shedding bark for unhealthy reasons will often also show vertical bark splitting, cankers, and open wounds.
Holes and “sawdust” at the base of the trunk
According to Riverbend, an important place to check to gauge a tree’s health is at its base where its trunk meets its roots, which is often called the trunk flare or the root collar. Due to this important connection to the roots, this area is crucial to the tree’s overall health.
Moreover, there are some telltale signs and common problems that can have potentially fatal effects for a tree if they go unchecked. And anyone who spots small holes like these with a fine power that looks like sawdust covering them should know that they’re signs of insect damage. In the case shown here, that damage proved extensive enough that the tree is essentially doomed.
Obscured trunk flare
Riverbend described the trunk flare as vital to the life and health of a tree, which is why it should be kept clear and free of debris at all times. For instance, this person has rightly planted this tree so its trunk flare is above the soil and not buried in mulch.
If a tree’s trunk flare doesn’t look like this or remains completely invisible, the tree is at serious risk of dying. That’s because that overburdening is a recipe for decay in the most ruinous part of the tree to experience it. It’s also the leading cause of tree death.
When left alone, it’s not unusual for a tree to grow shoots like the ones shown here from its lower trunk. These are called epicormic branches, and since they’re more parasitic than helpful, they’re typically just a sign that a tree is long overdue for pruning.
However, the Canadian Invasive Species Centre noted that if a tree is also experiencing branch dieback, bark deformities, yellowing leaves, and vertical cracks in the trunk, those epicormic branches have a much more concerning reason to exist. If some of those other symptoms are present, they’re likely a sign of the tree-killing emerald ash borer.
Proximity to power lines
If a tree’s limbs are hanging over or on top of power lines, they’re an accident waiting to happen. And it will effect so much more than the tree when a bad storm comes in. Although one effect seems obvious, the other is easier to forget.
According to Arbutus Tree Service, a tree that either falls or drops a limb on power lines is likely to cause a neighborhood black out. However, it’s also surprisingly easy for those downed power lines to spark, which can start a fire.
According to Truly Nolen Pest Control, carpenter ants are some of the worst ants to infest a home. Like termites, they’re known to weaken and destroy wood by tunneling through it. Although they’re commonly understood to eat wood, they really do this to create an elaborate escape network from predators.
Based on that description, it sounds like carpenter ants would be a dangerous pest for a tree. However, they aren’t known to tunnel into healthy trees. As such, they’re a sign of a dangerous tree because if they’re there, that tree is already dead, and their tunneling will likely make it collapse. That tree should be removed, but their presence suggests it should have been removed long ago.
Although this hazard is specific to fruit trees, it’s a worrying sign of a particularly destructive fungal infection. According to the University of Minnesota, the fungus in question is called Venturia inaequalis, but there are several different subspecies of it that only affect specific trees.
These spots are typically greenish-brown, and they often render the fruit inedible, but the real problem comes when they defoliate a tree three years in a row. At that point, the tree’s health is in danger, and fungicide is the last hope of saving it.
Small tunnels in the wood
According to Texas A&M University, intricate tunnels like the ones shown in this piece of wood are signs that boring insects like bark beetles and locust borers have infested a tree. And they’re also a sign that the tree in question needed to go a long time ago.
Although these boring insects can be quite destructive on their own, they’re known as secondary invaders. Since many of them prefer dead or dying wood, they’re usually a sign that another factor was responsible for the tree’s destruction.
It’s part of an at-risk species
Part of the reason that infestations and diseases can spread so easily in some forests is that they’re mostly composed of similar tree species. For instance, part of the reason that the emerald ash borer has proved so destructive has to do with past planting practices that have made some wooded areas composed entirely of ash trees.
As such, Cadieu Tree Experts suggested that at-risk tree species should be decreased in an area to make room for a more diverse planting strategy. That way, problems that affect a specific tree species affect a few trees, rather than an entire forest.
It grows too big for the area it’s in
It’s easy to underestimate how long it can take a tree to grow and how large it will get when it finally does. For that reason, it’s entirely possible to build a whole complex around a tree and not realize that the area isn’t big enough for both of them.
While it may seem like any overgrowth in this respect could be solved with tree cutting, the unfortunate truth is that complete tree removal is usually necessary when a large tree is interfering with structures around it. That’s because it’s roots are doing even more damage underground, which is also why professionals need to be involved in that removal.
It’s interfering with public safety
Some trees can cause damage to people’s property but others will find themselves in the bizarre position of making roads less safe simply by growing. And while this photos shows an obvious case of a tree’s growth consuming a stop sign, it’s usually not quite this dramatic.
More commonly, a tree’s branches will obstruct stop signs, street lights, and traffic lights. In such cases, it’s not unusual for municipal governments to decide that these problem trees need to be removed. They may be fine trees on their own, but they’re in the wrong place.
It’s an invasive species
Although much of the press about invasive species has to do with animals like the zebra mussel or the dreaded emerald ash borer, it’s also true that some trees can prove just as harmful to the ecosystems they’re introduced to. According to The Nature Conservancy, one example is called the Tree of Heaven.
It was brought stateside from China due to its rapid, easy growth and resistance to diseases and insect infestations. However, it turns out that it reproduces just as fast as it grows, and both crowds out other plants while introducing a chemical into the soil that’s toxic to them. It has to go, but that’s proving challenging.
Wet, soft bark
Although Riverbend is certainly quick to point out that cracked or missing bark can be a serious problem for trees, that’s not the only way their bark can warn arborists of a tree’s poor health. Sometimes, the tree’s bark is at its worst when it’s intact.
After all, bark that can be described as wet, soft, sunken, or swollen is likely experiencing decay. That’s because these overly moist, weakened conditions make for the perfect breeding ground for fungi that can start or accelerate that decay.