Trees provide many benefits, such as shade, beauty and less erosion to our landscapes. However, trees can also pose hazards if they become damaged or diseased.
Hazard trees are dangerous for many reasons. They can fall unexpectedly, causing significant property damage or worse, injuries.
Many tree defects are obvious, while others are more hidden.
It’s important to be aware of the warning signs so that you can take steps to mitigate the risk.
As arborists, we can help with hazard tree identification.
Here’s the list of 13 warning signs that your tree might fail:
1.Rotten or Decayed Wood
Look for any signs of decay, such as soft, hollowed, crumbly, darkened wood, cankers or mushrooms growing on the tree.
Discoloration or discolored spots from fungi can also indicate that the tree is decaying from within and should be inspected by a professional arborist.
Does your tree have any significant lean?
Whether caused by wind or root damage, heavily leaning trees typically require removal for safety reasons.
However, some trees may lean naturally and might not pose a threat if they grew at an angle from seedlings.
Another factor to consider is the direction of the leaning tree. The risk is greater if the tree leans towards a building, power line, or other structure.
3.Imbalanced Weight Distribution
Trees with imbalanced weight distribution or leans may indicate weakness and structural issues.
A poor tree structure is often caused by many years of storm damage, unusual growing conditions, improper pruning practices and other factors.
Watch out for imbalanced weight distribution on your tree because they’re more prone to fail.
4.Weak Union (Growing in Tight V Shape)
A weak union may be caused by two stems of roughly the same size that grow from the same point on the tree. We refer to this as ‘codominant stems’. These stems grow in a tight V shape, and oftentimes bark forms in the union between them, also known as ‘included bark’.
The junction between two stems/branches is the weakest point of the tree. It often looks as if the tree has two tops.
Unions are especially prone to failure in windy storms.
Cutting just one top of a tree isn’t the solution, as that could weaken the tree further and cause more damage.
In this case, having the tree cut down is generally the only optimal solution.
Root problems are often tricky to detect as they occur underground and are largely out of sight.
To detect root decay, look carefully for fungus on or near the base of the tree. Discolored or unusually small leaves are also symptoms that could be pointing to root problems.
If the soil around the roots has a fermented-like smell, it can also indicate root rot or unfavorable (anaerobic) soil conditions.
One of the most common disruptors to root health is soil compaction. Soil compaction affects the soil structure and reduces the availability of oxygen to the tree. It often occurs in areas where construction has taken place.
Construction equipment and excavation can also sever the roots and cause major disruptions to root systems underground.
Other factors that could comprise roots are prolonged drought or excessive water. Saturated water conditions over a prolonged period of time can promote root rot or drown the tree.
Damaged roots are vulnerable to organisms that may cause further decay/damage.
Trees with root problems are more likely to be blown over and are often candidates for removal.
6.Missing Bark or Big Cracks
Large cracks in the trunk of a tree can be an indication of structural weakness.
Look for any deep splits in the bark or so-called cankers. Cankers are dead areas on the trunk where the bark is missing or sunken, and they typically appear when a tree is dying.
The canker increases the chance of stem breaking and poses a hazard.
7.Missing Leaves Close to the Trunk
A healthy tree’s leaves fall from the outside inwards. So if you see missing leaves on the inside first, it could mean something is wrong with the roots.
Compromised roots can’t deliver nutrients and water, which are absolutely essential for any tree to thrive/survive.
Keep an eye out for irregularities in how leaves fall so you can take steps to remedy this issue before it becomes a much bigger problem.
When roots are exposed to the surface, they can easily be damaged. For example, they might be cut by lawnmowers.
Damaged roots cannot effectively collect water and nutrients – thus hindering their growth and strength, making them more prone to diseases or failure.
A solution to overcome this issue is spreading a thin layer of mulch/wood chips around the trunk of the tree to create a barrier for lawnmowers. It provides a breathable protective layer.
An added benefit is as the woodchips/mulch decomposes, it becomes full of nutrients for the tree.
Lightning strikes can cause various damages to a tree – from internal destruction to branch fractures and limb splits.
When lightning strikes, the heat causes internal damage to the tree. For this reason, many trees don’t survive a significant lightning strike unless there is an adequate lightning protection mechanism installed in place.
If you notice that the tree has been struck by lightning, it’s best you get your tree checked by an arborist to assess the extent of the damage.
10.Insect Infestation in the Tree
Dead and hollowed-out parts of trees provide perfect nesting sites for some insect colonies. So if you notice an excessive amount of insects in the tree, there’s likely decay somewhere in its structure.
Insects tend to multiply and cause further damage by taking advantage of vulnerable trees.
There are several steps you can take to get rid of pests.
However, before beginning any treatment process to eliminate an infestation in a tree, an arborist can help you evaluate if it’s worth saving a tree or if removal would be necessary.
11.Vines Growing Over Tree
Aesthetically speaking, some people may find vines growing over their trees pleasant to the eye.
However, when the vines excessively cover the roots and tree, they may block the sunlight and “suffocate” the tree.
Add dead leaves and moisture on the roots, and you have a perfect combination for fungal, bacterial diseases or structural damage.
Vines also make it harder to spot any tree effects.
That’s why keeping vines away from trees is a good idea. The sooner you stop them, the better.
12.Dead or Falling Branches
Falling branches are another hazard tree identification sign you want to watch out for.
Dead or dying branches are more prone to falling off and should be removed promptly.
They can also indicate bigger underlying issues, such as root rot, disease, pests, or fungal infection. Removing dead branches prevents the problem from spreading and further weakening the tree.
All it takes is one storm, and tree branches could end up falling onto your house.
Unfortunately, there is no way to foresee when the dead tree branches will fall, so it’s best to take care of it sooner rather than later.
13.Hollows in the Tree
Hollow spots in the trunk are called cavities. Cavities can be caused by various reasons, but one of the most common is decay from improper pruning.
Cavity weakens the tree making it less resilient to storms and strong winds.
Insects will often target hollowed-out areas and use them as their entryway, so if you spot a cavity in your tree, it’s best to have an arborist inspect it.
Unlike regular wood, decayed wood is soft, mushy, crumbling, or may be completely missing, leaving a hollow or cavity.
Small amounts of decay and rot do not necessarily mean the tree is hazardous, but large amounts of rotten wood should not be ignored.
However, if you identify solid wood surrounding the hollow cavity, there might still be hope! In this case, the tree has a lower chance of breaking off or falling over.
Final Word: Hazard Tree Identification
There are multiple reasons why a tree may fail, such as:
- Poor soil condition
- Improper planting condition
- Old age
- Flooding or drought
- Construction damage
- Insect infestation
It can sometimes be challenging for the untrained eye to identify the defects or tree hazards, but if you suspect you have a hazardous tree, take action as soon as possible.