Got trees? If you do, you’ll want to learn how to evaluate whether or not your trees pose a safety risk for you and your family. Learning to identify a dangerous tree, including the risks and defects to look for, before it becomes a serious problem can save your trees, your property, and your cash. Read on to learn when it’s time to relax in your garden and when it’s time to call an arborist to take care of a hazardous tree.
In This Article …
- What to evaluate on different parts of the tree when looking for potential tree risks, including
- Trunk flare
- Determining whether or not the tree is a hazard (not all dangerous trees are hazard trees)
- Things to know before evaluating your trees
- When it’s time to call in an arborist
- Why an arborist with the Tree Risk Assessment Qualification is a good choice
How to Evaluate Your Trees
Healthy trees are valuable landscape assets but damaged or unsafe trees can be expensive hazards. But how do you know if your trees are dangerous? You inspect them!
Ideally, you should inspect all trees on your property every year. You can do it at any time of year, leaf-on or leaf-off. However, to be thorough, it’s best to inspect trees after leaf drop in fall, after leaf-out in spring, and after severe storms. Inspecting your trees is an ongoing process that will help you catch any potential problems before they become unsafe or untreatable.
Inspect trees carefully and systematically. Examine all parts of the tree, including the roots, root or trunk flare, main stem and bark, the overall canopy, and individual branches. Be sure to examine all sides of the tree. Use a pair of binoculars to see branches high off the ground.
Let’s start from the ground up with the things to look for when examining your trees –
Are your tree’s roots intact, or have they been cut off to install a sidewalk, driveway, or patio? Trees whose root systems have been damaged or improperly cut off are more likely to topple over in a storm or when the soil around them is saturated with water.
Do you see tree roots growing at the soil surface? Shallow surface roots can result from insufficient irrigation that doesn’t soak down into the soil where tree roots should be, and shallow roots won’t anchor your tree as securely as deep roots will.
Is the ground level around the tree, or are there signs of heaving or cracks in the soil? When roots on one side of a tree decay or are damaged, it often starts to lean. One of the first signs of leaning is raised or disturbed soil on one side of the tree (where roots are starting to pull out of the ground).
Trunk flare or root collar
This is the area at the base of a tree’s trunk where roots start growing, and its vital to your tree’s health.
Check for signs of insect damage such as little piles of sawdust or small holes that weep sap. (You’re more likely to see the signs of insect damage than the insects themselves.)
And always keep the trunk flare visible and clear of debris—it should never be buried under soil or covered with mulch. Burying the trunk flare leads to decay and is the most common cause of tree death! If you can’t see the root flare, there’s a higher risk that the tree will be dangerous.
Your tree’s bark is like its skin—it’s a protective layer that keeps the tree’s interior safe. But sometimes insect pests or disease pathogens may breach your tree’s bark and damage its interior wood. This usually happens when the bark is damaged, such as by mowers or string trimmers, being hit by vehicles or construction equipment, a lightning strike, or when people nail or tie things to the tree (please don’t do this!).
Look for these signs of bark damage that could indicate a dangerous tree:
- bark cracks
- areas of missing bark
- areas of bark that look soft, sunken, swollen, or wet
When a deep crack extends into the interior of the tree, it usually indicates that the tree is already failing. Cankers (sunken areas in the bark caused by wounding or disease) increase the risk of the branch breaking.
And if you see mushrooms growing on the bark, you’ll know you’re seeing decay in action.
A trees’ crown is made up of its branches and its foliage. It should have an even, natural-looking shape and spread. Some signs of potential structural problems include:
- an unbalanced crown, with more growth on one side as compared to the other
- one or more long, heavy branches hanging over a building or place where people gather
- two or more main trunks or large branches growing in a very narrow “V” shape (a narrow crotch)
All of these can mean the tree is less stable overall, and more likely to blow over or break in a storm. Luckily, these are problems that can be fixed by a certified arborist with proper pruning and/or cabling to support long or weak branches.
You should also look for signs of tree health problems and active insect infestations, such as:
- stunted or yellowed leaves
- bare branches
- twig or branch die-back
- skeletonized leaves
- ragged or damaged leaves
A tree’s branch structure should be evenly distributed along its trunk, with large branches tapering and dividing into small branches and twigs. Branches should be full of healthy, green leaves all the way to the branch tips.
The critical thing to look for is dead or broken branches—these can fall to the ground at any time! And if you notice any dead branches that have broken off and are still lodged or hanging in the tree, be extremely careful. There’s a reason these are called “widow-makers.”
Is the tree a hazard?
Just because a tree has damage or defects, that doesn’t mean it’s a hazard tree. A dead, dying, or diseased tree is only considered a hazard if it’s located within falling range of property or people.
If the tree is on your property, you’re responsible for its maintenance. You could also be financially liable for any damage or injury to people or property if the tree fails.
Hazard trees don’t necessarily need to be removed, but it takes a trained arborist to decide on the best course of action to deal with these dangerous trees.
NOTE: Most homeowners are not trained or equipped to evaluate, diagnose, and treat unsafe or hazard trees, especially large or mature trees. There’s a high risk of severe injuries to the homeowner and damage to their trees – it’s a risk that’s not worth taking.
What else should I know?
It’s not always easy to identify a dangerous tree. Sometimes, it’s better to bring in an arborist to check your tree(s) for defects and possible risks. As you examine your trees, think about the following:
- Your familiarity with tree and disease identification – The more you know, the better able you are to correctly identify structural defects and tree damage that make it unsafe, or signs of pest, disease, or environmental problems that affect the health and safety of your trees. Some of the most dangerous conditions are difficult for less-experienced people to notice or identify.
- Your tree care experience–Many tree defects require remediation with proper tree pruning, cabling, and/or damage restoration techniques.
- If you’re a homeowner– You’ll generally be liable for any damage caused by an unsafe tree, whether you knew it was unsafe or not.
- The size of your trees – The larger the tree, the more likely it is to cause serious damage if it fails. Arborists, such as the tree care professionals at Riverbend, have the cranes and other equipment needed to safely assess and work with large trees, including those that are structurally compromised.
- The location of your trees – Trees located near buildings, roadways, public areas, or power lines pose a far greater risk to their surroundings than a tree growing in a large, empty area.
- The age of your tree – Trees are living organisms subject to constant stress. Older trees are more likely to have accumulated multiple defects and extensive decay, even if it’s not obvious.
When to Call an Arborist to Examine Your Trees
Just because a tree has plenty of green leaves doesn’t ensure that the tree is safe. Tree trunks and branches can be quite defective and still support a lush green crown. On the other hand, a tree with multiple defects may not actually be dangerous.
That’s where a qualified arborist comes in. If you notice any of the potential tree problems listed above, the best step is to call a certified arborist to evaluate your trees.
It’s especially important to call an arborist if you see any of the following signs that indicate advanced decay or particularly dangerous situations:
- A broken branch is hung up in the tree canopy
- There are dead branches, particularly those greater than about 4” in diameter (these can do extensive damage when they fall)
- The tree has multiple deep cracks or splits in the bark, or a deep crack on a large branch
- There are large, decayed areas on the trunk, branches, or root flare
- The tree is leaning
- More than half of the roots have been removed or damaged
- There’s a very large branch hanging over your home, patio, roadway, etc.
Arborists are trained professionals who can:
- Identify tree species
- Recognize tree hazards, imminent or future
- Identify and diagnose insect pests and fungal diseases
- Prune trees to mitigate tree damage, rejuvenate growth, and remove hazardous branches
- Provide honest information about when a tree is worth saving and when it should be removed.
Why should I use an arborist to evaluate a dangerous tree?
Certified arborists are bound by a code of professional ethics, something unlicensed or bargain-rate “tree trimmers” are not. Certified arborists also only perform work that is necessary and will never offer to “top” your trees or perform any work that is detrimental to tree health.
The cost of an arborist consultation will save you money in the long run, as you’ll receive an accurate diagnosis and professional recommendations for what steps you should take with your trees. You may be surprised to learn that not all “dangerous trees” actually pose significant risk; sometimes the issues can be dealt with without removing the tree.
Trees are valuable assets that increase your property value and add appeal to your landscape. But their value, and their health, can be compromised or lost if damage or disease is left untreated. Poor-quality or damaging tree work performed by untrained tree trimmers can also compromise the tree’s safety.
What’s a Tree Risk Assessment Qualification?
The Tree Risk Assessment Qualification (TRAQ) is an advanced credential earned through the International Society of Arboriculture. It certifies that the individual demonstrates professional knowledge in tree risk assessment. It gives Certified Arborists a standardized, systematic process for assessing tree risk to determine whether or not a dangerous tree poses unacceptable risk. A TRAQ credentialed arborist will help you make an informed decision about your tree, with a focus on the safety of people and property, as well as tree benefits, health, and longevity.
If you’re concerned about the safety of your tree and want to understand all of your options, your best option is to work with a TRAQ credentialed arborist.
Call Riverbend Landscapes & Tree Service and set up an appointment with Peter Hart (ISA Certified Arborist, TRAQ); he’ll give you the straight scoop on your tree.
Need Some Professional Advice?
Give us a call! We’re here to help make your garden beautiful and keep it healthy. Caring for plants and trees is our passion—as is building long-term relationships with our clients!
We’ll schedule a convenient time to come out and evaluate your trees and shrubs. Based on our inspection, we’ll tell you if your trees are unsafe and need immediate attention. Or, perhaps they just some extra fertilization or corrective pruning. The bonus is that many people become more appreciative and more aware of their garden once they start learning about the plants and trees they have.
Give Us a Call at 703-402-9366
If you'd like help with your trees or landscape, have any questions, or would like to schedule an appointment with one of our Certified Arborists, please give us a call. We'd love to hear from you!
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About The Author
Landscaping is in Logan’s blood. Growing up in Great Falls, Logan’s passion for the field was fostered by his family of professional landscapers. This early introduction gave him an appreciation for both the science and aesthetic aspects of the field. After earning his business management degree form the University of Mary Washington, Logan combined his academic and practical landscaping experience to found Riverbend Landscape and Tree Service.