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How to Tell if a Tree is Dangerous

Dangerous trees cause unfortunate damage, injuries, and sometimes death. It’s important to identify dangerous trees so that they can be properly and safely removed. We’ve written a guide to identify when a tree is dangerous, with things you can easily spot with your naked eye.

Approaching this task by splitting the tree into different areas can identify anything that’s not right easier. First, the tree as a whole should be looked at from a distance. From this perspective, focus simply on how the whole tree looks, rather than any specific parts. Important things to check for are whether the tree is leaning particularly far in a certain direction, more so than normal if it normally leans a certain way, any large, dead branches, or any patches of dead or no leaves.

The ground around the tree is the next area to look at, focusing on the visible roots and the first three feet or so of the trunk. Some indicators of dangerous trees you could see in this area are cracked, and raised soil, which is a sign of a tree uprooting, and fungus, which is an indicator of a rotten trunk or roots – a tree decaying at the roots is at a dangerous risk of falling over.

The trunk as a whole is the third area to focus on and should be inspected thoroughly. The trunk is the source of many indications of a dangerous tree. Cavities, natural holes which form on the trunk, can be dangerous if they are too deep. Splits and cracks to the trunk can cause a tree to break apart or fall. Any areas of missing bark are usually an indicator of a dead section, which could be a surface wound or an infection.

Finally, check the branches and leaves, making sure to check the whole length of the branches, from where they connect to the tree to the tips. Dead branches are the most obvious indicator of a dangerous tree from this area and are the branches that have dying or no leaves, and if it’s been dead for a long time, no bark. These branches are dangerous as they can easily break and fall off, potentially doing serious damage depending on their size.

The 7 Tree Hazards to Look For

Concerns that a tree might fall and damage your property, or even worse, hurt a person, are serious. Tree hazards are also a liability. If your tree, or one of its limbs, damages someone else’s property or hurts another person, that could easily result in a costly lawsuit.

Whether you’re worried, or you just want to be sure, the last thing you want to do is neglect it and assume everything is okay. You want to follow through on having your tree inspected and determined if it is really dangerous or if some of the issues you’re noticing aren’t true causes for concern.

While this article is by no means meant to be a replacement for having your trees inspected by a professional tree inspector, we hope that by providing some of the common tree hazards, you might recognize how to tell if a tree is dangerous.

Spotting a problem early, and getting a professional on your property for a tree inspection, can reduce your chances of having a serious issue. Even when you’re in doubt about a potential problem with your tree, it’s always best to err on the side of caution when it comes to something this important.

Here are seven tree hazards to watch for in the trees on your property.

Hanging, Broken, or Damaged Limbs

Probably the most visible (and most obvious) of the tree hazards, a broken or hanging limb, is a telltale sign that your tree is, in fact, a danger. However, limb damage isn’t always so obvious. A professional tree inspector will look for splits and cracks to determine how severe the damage is.

A good tree inspector will bring binoculars to get a closer look at some of the upper limbs. Because fall-risk limbs are not as easy to diagnose as some might believe, this is a prime example of why a tree inspection is important, even if you don’t have hanging or broken limbs.

Dead Limbs

It’s not just hanging or damaged limbs that pose a fall risk. Limbs in your tree may be dead without you even realizing it, and these can eventually fall as well.

How to tell if a tree is dangerous and how a tree inspection can spot hazards.

The scary truth is that dead limbs can remain in a tree for years with the decay continuously spreading to live tissue, worsening and deepening the problem—and the danger—unbeknownst to you.

Changes in the Bark

Included bark, or “ingrown bark tissues,” can develop where two or more stems grow closer together. When this occurs, it can create a “V” formation and be more likely to split or break (as opposed to a more normal “U” formation that a professional would look for). Although proper pruning can prevent this from happening, it’s not uncommon to find that trees were improperly pruned over the years. Improper pruning can also lead to decay, damaged, or weakened areas of the tree.

A professional will look for included bark during a tree inspection and determine whether it is a concern. A professional will also look for any discoloured bark or peeling bark, as these can be potential signs of disease, such as a fungus. Though some trees naturally shed their bark, this is not true of all species, making this a nuance for a professional to examine.

A Tree that Leans

If you have a tree that is leaning, a professional will take into account many factors, the most important of which is how long has it been leaning. Has it been this way for a long time, or is this a new change? And, does it continue to change? Is it leaning more today than it was last week? These are the types of questions that you will likely be asked during a tree inspection, and the responses will make a difference in the overall assessment of your tree’s safety.

A tree inspector will also take into account what the tree is leaning toward. Is it right over your house? Your car? An area where the kids play? Or is it in the far back of your property where, should it fall, it has no chance of doing harm? These factors will also come into play in making a decision on the seriousness of your tree issue and the best course of action. Some trees do have a natural lean to them, and it may not be a concern. But it’s worth a professional opinion.

Root Damage

Tree roots are sometimes unknowingly damaged during construction activities. But problems may not actually manifest until years, even decades later. That means damage to a tree in your yard could have been done before you even lived there.

Roots are the most vital aspect of the tree, and if they are damaged by construction equipment during a project, the entire tree could eventually die. Some signs of root damage include wilting, as the tree’s ability to take in moisture has been damaged. Thinning foliage, undersized leaves, dead branches, and limited growth are all signs that the tree’s roots may have been damaged. Of course, these issues can also be signs of other problems that only a professional might distinguish.

Exposed, Weakened Trees

Clearing trees during the construction phase can also cause problems for the remaining trees on the property. For instance, if the lot is wooded and part of those woods were cleared, the remaining trees (that may have once been situated in the middle of the woods) are now right on the edge of the construction line. Those trees previously had a windbreak when the other trees were there. Now that they are exposed, they are more susceptible to wind damage.

It’s not to say that these trees won’t survive, but these trees are often overlooked and should be inspected regularly in the following years.

Poor Structure

In a forest, trees compete for the sunlight and grow very tall without quite so many branches. However, outside of its natural habitat, a tree in your backyard typically develops a wide crown with a lot of large lower branches and limbs. Unfortunately, an overburdened canopy and a significant amount of large limbs can structurally weaken the tree over time.

Trees with the poor structure are typically the first to break or fall during a storm. But they can actually become a hazard at any time. Your tree’s structure should be evaluated to determine if it poses any risks now or in the future.

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What Causes A Tree To Fall? 

There are tree failures that are easily predictable, though most risks can be mitigated by keeping watch for any red flags. Pay attention to the following while you are inspecting your trees: 

Tree Health – You can foresee any structural problems by taking a closer look at the tree’s overall health. This includes the foliage colour, foliage density, signs of infection, and its vigour. Some serious telltale signs of a dying tree include large, dead branches, thin leaf coverings, oddly-shaped leaves, and fungus all over the bark. 

Tree Defects – Be sure to inspect the tree for any defects by thoroughly checking the crown and trunk down to the roots. A clear indication of a potential hazard is if there are dead branches along with the tree’s crown, which is commonly called widowmakers. It’s an ominous name that serves as a warning to passers-by as defects can cause branches to fall even on a clear and calm day. 

Other signs that indicate impending issues are cracks and split along the tree’s trunks. Root rot is one of the most important factors to consider, so be extra vigilant in inspecting the base of the trunk for any evidence of root defects like cracking, heaving soil, or growing mushrooms. 

Improper Pruning – Poor pruning techniques can weaken branches, which can lead to a decline in the tree’s health. 

Site Conditions – The planting location plays a significant role in a tree’s health, as any construction within the tree’s root zone can compromise its ability to support the weight of the entire tree. 

Targets – These refer to the potential damage to valuable targets like people and property. A tree placed over a playground, near a sidewalk, or next to a driveway are samples of high-risk targets. 

Keep in mind that tree inspection is highly recommended before and after storms, heavy snowfall, flooding, and other natural calamities. 

Things to check for on a dead tree

The first thing that you need to do is inspect the actual tree in question. There are a few visual signs that will help you out as well as some tests you can perform on the tree itself.

Fungus Growth

Take a look around the tree’s trunk and base of the trunk. Do you see any fungus growing? Fungus is an initial sign that the tree could be dead. If you spot fungus on the trunk, this is often an indication that the internals of the tree trunk is actually rotted out, and anything beyond the living fungus is dead.

Tree Trunk Damage

Keeping your focus on the actual tree trunk itself give it a good visual inspection. Look for cracks that are running vertically along with it. If the trunk has severe damage, this increases the likelihood that the tree is in bad health. Check to see if the tree has bark. As trees age, bark will fall off of the trunk and, if healthy, grow back to replace the old stuff. If a tree isn’t as healthy, you will see areas, large or small, on the trunk that are just smooth areas of wood with no bark covering it.

Check for Bare Branches

Take a look at the trees’ branches. If they’re abnormally bare during a time when they shouldn’t be – such as Spring or Summer – there’s a good chance the tree is too far gone to save. Sometimes branches on only half of a tree are bare, and the other side is full. This would signal that the tree is diseased only on one side, which case could cause a tree to become lopsided and fall due to the weight. If the tree is deciduous, check to see if the leaves cling onto the branches in the winter instead of falling off, as this is another sign the tree may be dead.

Check for Damaged Roots

While performing a check of the roots to see if they are damaged is not easy, there are some factors that could help you guess if the roots could be damaged. An initial sign that a trees’ roots may be damaged is if the tree appears to be leaning to one side or the other. This could mean the tree’s roots are not strong enough to keep it directly upright. If the roots are damaged or weak, epicormic shoots could be present at the base of the trunk. These are sprouts that can pop up and mean that the tree is under severe pressure underneath the ground. There are some other factors that could affect a trees roots, both natural and man-made. Things like excavation projects, new construction, shallow root systems, exposure to new extreme elements, or loosened soil compaction. Check to see if any of those are present near the tree area.

Perform Scratch or Break Test

Performing a scratch test is an easy way to tell the health of a tree. Use a small knife to scratch the outside of one of the tree’s branches. If the inside is green and moist, the tree is healthy. Try this on a few more branches in different areas of the tree. If they are all green and moist, the tree is in good shape. You can also perform a brake test which is the same thing, except instead of scratching the outside, you can attempt to break the branches to check the inside.

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