Few things are as heartbreaking as watching a tree you’ve known and loved for years — perhaps decades — start to decline.
Unfortunately, there are a variety of things that can cause trees to die in Michigan. Many of these causes can be addressed, but you have to positively identify the culprit and initiate a treatment regimen quickly to have any chance of saving the tree.
This is why it is always wise to contact an ISA-certified arborist at the first sign of trouble. The arborist can then assess your tree and provide a recommended treatment or management plan.
We’ll share a few of the leading causes for tree death in Michigan, as well as some of the common signs and symptoms to watch for.
Pests and Pathogens: Biotic Causes of Michigan Tree Death
Trees may experience failing health for a variety of reasons, but the culprit will either be living (biotic) or nonliving (abiotic). We’ll address some of the most common biotic causes for tree death in Michigan — namely, pests, fungi, and diseases — first.
Armillaria Root Rot
Armillaria rot is a fungal disease that can affect a wide range of Michigan tree species. The fungus that causes the disease can be found in just about any soil, especially those within or bordering forested areas.
Typically, Armillaria root rot only causes problems for trees that are stressed by other factors, such as flooded soils or droughts. However, once the disease takes hold, it is quite difficult to treat. Supportive measures are often all that can be done.
Signs to Watch For:
- Crown dieback or premature leaf drop
- Wilting or curling leaves
- Mushrooms or conks near the roots or trunk
Phytophthora Root Rot
Caused by a variety of fungal species in the genus Phytophthora, this disease is often associated with water-logged soils. In some cases, it can lead to the rapid decay of a tree’s roots (and sometimes the base of the trunk), which can make the tree susceptible to collapse or wind-throw.
This is another common disease of Michigan trees that isn’t easy to completely eliminate. Treatment usually entails supporting the tree’s overall health.
Signs to Watch For:
- Wilted leaves
- A sour odor near the roots
- Cankers or lesions near the roots, trunk, or branches
Girdling Roots
While a tree’s roots are undoubtedly important, they can cause serious problems in some cases, such as when they wrap around the trunk or primary roots. This eventually “strangles” the trunk or roots and prevents water or nutrients from traveling through the affected tissues.
Girdling roots are probably most common in trees that are planted too deeply, but they can also occur in trees that are raised in containers for an extended time period before being planted in the ground.
Signs to Watch For:
- Uneven crown development
- Discolored or small leaves
- Swelling near the base of the tree
Emerald Ash Borer (EAB)
One of the most destructive pest species of Michigan trees, the emerald ash borer is a small beetle species that feeds on the cambium (inner bark) of ash trees during its larval life stage. Originally native to East Asia, the beetle was first discovered in Michigan in 2002.
Sadly, infested trees will almost always die within two to four years. Treatments are available, but they must be started at the earliest stages of the infestation.
Signs to Watch For:
- Canopy thinning or premature leaf drop
- D-shaped exit holes from the bark (made by the beetles emerging from the trunk)
- Frass (insect droppings) at the base of the tree
Dutch Elm Disease (DED)
Dutch Elm Disease is caused by a non-native fungus that originally hails from Asia. First documented in the U.S. back in the late 1920s, the fungus has caused widespread die offs of many native ash species. The disease is spread by the activity of elm bark beetles, and it typically causes trees to die within a few years of the initial infection.
Treatments for the disease — including aggressive pruning and fungicide injections — are available, but they must be initiated very quickly.
Signs to Watch For:
- Early leaf drop
- Wilting or yellowing leaves
- Progressive branch dieback (starting at the tips and progressing to the trunk)
Oak Wilt
Oak wilt is a disease that primarily affects oak trees. It can attack any oak species, but it is most problematic for those in the red oak group, such as the northern red oak, black oak, and northern pin oak. Caused by a fungus known as Bretziella fagacearum, the disease can cause extremely rapid decline, with some trees dying in a matter of weeks.
Fungicidal treatments can help slow the progression of the disease, but there is only a narrow window of time during which treatment is effective. This means that prevention is especially important for this disease, which includes doing things like addressing infected trees quickly and pruning trees during the proper time of year.
Signs to Watch For:
- Leaf wilting or browning
- V-shaped discoloration of the leaf tips
- Asymmetrical dieback patterns in the tree
Environmental Threats: Abiotic Causes of Michigan Tree Death
The counterpart to biotic causes of tree death, abiotic causes are created by non-living factors in the environment. These triggers are more likely to impact an assortment of different trees on your property, rather than a single species.
Inappropriate Species Selection for the Location
Unfortunately, some trees are doomed to struggle from the moment they’re planted. This often occurs because the trees are simply planted in an area that’s poorly suited for meeting the tree’s needs. For example, the soil may be too dry, too damp, or the soil chemistry may not be ideal for the species.
There is often little that can be done in these cases, aside from transplanting the trees to a better location (though this is rarely feasible for large trees). This highlights the importance of discussing tree plantings with an ISA-certified arborist beforehand.
Signs to Watch For:
- Stunted growth
- Premature leaf drop
- Brown, yellow, or “scorched” leaves
Drought
Droughts prevent trees from absorbing sufficient water through their roots. Over the short term, this results in trees with wilting leaves and twigs, but extended droughts may cause trees to reach something called the “permanent wilting point.”
From this point forward, there is nothing you can do to save the tree, and it will undoubtedly perish.
Signs to Watch For:
- Wilting, yellowing, or curling leaves
- Stunted growth
- Drooping branches
Floods
The flip side of droughts, floods can also cause trees to die in some cases. Flooding not only prevents a tree’s roots from accessing oxygen, but the waters may also disturb the integrity of the soil, thereby placing the trees at risk of being blown over in the wind. Some trees, such as black willows and yellow birches, commonly grow in floodplains, so they tend to withstand flooding better than other species, such as white oaks and most native pines.
There is rarely anything that can be done to save trees growing in flooded areas. The best approach is generally to support the tree’s overall health and hope for the best.
Signs to Watch For:
- Shallow root growth
- Root rots (primarily apparent in the form of mushrooms growing near the root zone)
- Increased lean or movement in the wind
Soil Compaction
Soil compaction is an incredibly common problem that afflicts trees in urban and suburban areas. Caused by a variety of different human activities, ranging from heavy foot traffic to construction activities, compacted soils prevent a tree’s roots from growing properly and accessing enough oxygen, and they may also fail to have access to sufficient water.
There are a few ways arborists can help address compacted soil, such as radial or vertical trenching around or within the root zone. Fortunately, when initiated early, these techniques are often quite effective.
Signs to Watch For:
- Shallow root systems
- Stunted or slow growth
- Cracking or lifting soil
Air Pollution
Many trees suffer if exposed to air that contains high levels of ozone, nitrogen dioxide, or sulfur dioxide, among other harmful chemicals. While few trees thrive when exposed to these kinds of pollutants, some Michigan trees fare worse than others. For example, maples, red oaks, and white pines are particularly sensitive to polluted air, while Kentucky coffeetrees and tuliptrees can sometimes survive when planted in areas with polluted air.
There is not much that can be done to correct problems associated with air pollution; proper species selection at the time of planting is generally the only effective strategy for preventing this issue.
Signs to Watch For:
- Leaves that are yellow or feature brown spots
- Premature leaf drop
- Reduced flower or fruit production
Poisoning
Whether carried out deliberately or accidentally, poisoning is always an important possibility to consider when trying to identify the cause for a tree’s failing health. Various herbicides are often the poison of choice for those deliberately trying to harm trees, but paints, solvents, oil, gasoline, and even road salts can also poison trees.
There aren’t many effective treatment strategies for trees that have been poisoned, but supportive care may help in some cases.
Signs to Watch For:
- Leaf discoloration (color may vary depending on the poison in question)
- Wilting leaves or branches
- Bark abnormalities, such as cracking or peeling
Nutrient Deficiencies
Nutrient deficiencies often prevent trees from thriving or growing as fast as they should, but they generally don’t cause a tree’s death unless they are quite severe. However, nutrient deficiencies can also cause a tree to become stressed, which may predispose the tree to other threats, such as pests or disease.
Nutrient deficiencies are often relatively easy to address with soil amendments, fertilizer application, or other techniques. However, it is imperative that you have a certified arborist perform soil testing first to ensure you are addressing the actual deficiency; indiscriminately applying amendments or fertilizers rarely helps, and it can even worsen existing problems.
Signs to Watch For:
- Yellow, red, or purple leaf coloration
- Small leaves
- Leaf curling or necrosis
What Can You Do in the Meantime?
Again, it is critical to contact an ISA-certified arborist any time that you suspect one of your trees is in decline. Many common causes of tree death in Michigan can be addressed, but prompt action is required.
However, we find that many homeowners and property managers want to be proactive while waiting for a formal assessment and diagnosis. And while there aren’t many things you can or should do in the meantime, there are a few steps that are unlikely to cause harm and may even prove helpful.
- Keep safety in mind. Trees that are battling pests, disease, or environmental stresses may not be structurally sound, which can cause them to shed large branches or fall over entirely. So, do whatever you can to keep people, pets, and vehicles away from the tree until you have it assessed.
- Document any signs of symptoms you notice. Some signs and symptoms of tree-related problems can be short-lived, which will present additional challenges for the arborist who shows up at your home. So, while keeping safety in mind, try to photograph things like insects or mushrooms when possible.
- Observe the other trees on your property. Both biotic and abiotic tree threats often affect multiple trees at the same time. So, inspect the other trees on your property and look for signs of trouble, ranging from thin canopies to insect infestations to mushrooms.
- Gather any information about the tree you may have. It is often helpful for arborists to know the approximate age of a tree, as well as information regarding the specific cultivar in question. So, look through any records you may have (such as receipts or landscaping plans) and collect any pertinent information you can.
Contact Longtree Tree Services Now to Get Your Trees the Help They Need!
You don’t have to sit powerlessly while waiting to see if your tree is going to survive – the tree-care professionals at Longtree Tree Services are ready to help! Simply request a free consultation to start the process and give your trees the best chance of recovery possible!
