10 Early Symptoms of a Dying Oak Tree: Prevention Guide

Two oak trees close together on field in susnset

There is nothing more beautiful than a healthy oak tree that’s standing tall and full. With its beautiful green foliage, and branches stretching far and wide into the sky, an oak tree is a true symbol of strength. However, sometimes our oaks aren’t doing so great – and there are some key symptoms of a dying oak tree that you can look out for!

Symptoms of a dying oak tree can include yellowing leaves, loss of foliage, decaying bark, root rot, and more. For oak trees seriously affected, the trees will need to be removed from the property, while those only slightly affected can be monitored and nourished.

Today we’re going to talk about some early symptoms to look out for and what to do if you notice these signs! But first – keep on reading to learn a little bit more about oaks! 

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What Are Oak Trees?

Oak trees are those beautiful grand and wide trees that have lobed leaves and a ton of acorns! Known as a staple tree in American agriculture, oak trees are a symbol of great strength, wisdom, and resilience and can be found in almost every state across the United States of America. 

Oak trees are part of the Quercus family, with variations of up to five hundred plus types of oaks. All considered medium to tall, and with each type having a different growth rate, oak trees can get up to 100 feet at their tallest and are typically considered mature anywhere from 60-100 feet. 

Oak trees can be categorized into two main groups: White Oak or Red Oak. 

Oaks trees truly embody strength. They can withstand extremely strong winds and can even survive a drought. Oak trees live hundreds and hundreds of years, and one reason for that is because they are generally not susceptible to fungus or disease. 

However, disease does happen on occasion, and when they are dying, there are signs that we can look out for, but first – what is a healthy tree even supposed to look like?

How to Tell That an Oak Tree is Healthy

Before identifying what an unhealthy oak tree looks like, it’s important to know what a healthy tree is supposed to look like.

This way, you have a general rule of thumb before deeming a tree unhealthy.

There are three key visual ways you can identify a healthy oak tree: full branches, strong bark, and green leaves. 

To identify a healthy oak, think full, strong, and green! Using these three ideas as a basis for a healthy tree can help you quickly identify if anything is going on with your trees that would otherwise make them unhealthy. 

Full Branches 

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Big old oak tree on a meadow with forest behind.

In the image above, take note of the fullness of the majority of the bottom branches. However, notice at the top where the branches lack leaves? This is a sign where this tree may be reaching it’s end.

One of the tale-tell signs of a healthy tree is its branches! If the branches are full, you most likely have a healthy tree. 

A great way to double-check the strength of an oak tree branch is to take a branch and bend it. If it bends and feels flexible, it’s a living branch; a dead branch will snap immediately. Oak trees, in general, have a plethora of branches stemming from the center of the tree.

Strong Bark 

A strong bark is another great visual identification of a healthy tree. Strong oak tree bark has no peeling or decay and will remain its natural color. If the bark on your oak tree is changing color or starting to lose bark, the tree could be in trouble.

Green Leaves

Often, discoloration is the first sign of an unhealthy oak tree.

An oak tree has lobed leaves, and the leaves will vary between the type of oaks in leaves shade of green. A healthy oak tree will have an abundance of green leaves and will not show discoloration. Commonly, oak trees can contract Fusiform Rust.

But it’s time to dive into it – what are some early symptoms of a dying oak tree?

Early Symptoms of a Dying Oak Tree 

There are many symptoms to look out for, for a dying oak tree, and luckily, if caught early enough, there are solutions you can try to save your oak.

Check out this table below with some symptoms, causes, and solutions to help save your oak tree.

DYING OAK TREE SYMPTOMCAUSESOLUTION
Spots on Early LeavesAnthracnoseRake and Monitor
Blotches on LeavesTubakia Leaf SpotPrune Trees
Yellow, Brown, or Dull Green Perimeter on LeavesOak WiltTrenching and Trunk Injections
Puckered areas on LeavesOak Leaf BlisterRake Fallen Leaves and Debris
Swollen Branches or TrunkCrown GallControl Insects
White Textured SpottingArmillaria Root RotProper Irrigation
Peeling BarkRoot RotMaintaining Soil Drainage
Mushrooms at CollarHeart RotPruning of Infected Branches
Vertical Stripes on Branches or TrunkHypoxylon CankerProper fertility and Irrigation
Tiny Yellow Spotting on Trunk or LeavesFusiform RustFungicides

Spots on Early Leaves (Anthracnose)

Caused by Anthracnose – spotting, or lesions, on early leaves is a sign that the tree may not do so well – however, it’s not a game-ender quite yet. 

On an oak tree, Anthracnose can be noticed by looking at the leaf. You may see some yellowing or brown spots going along the veins of the leaf. The leaf itself may start to turn into a cup shape and feel papery. 

The solution to Anthracnose on an oak tree is to watch, monitor and truly, – see what happens. However, to get ahead, start by raking up the fallen leaves, and pruning branches that are lower to the ground. This keeps affected leaves away from others. 

Pruning branches can help air circulation. Increasing the air circulation can lead to proper irrigation and fertility of the tree.

If you’re interested, you can read our piece on the lifespan for common oak trees here.

Blotches on Leaves (Tubakia Leaf Spot)

Next time you’re out for a walk, take a close look at your oak tree. You may notice blotches on your oak’s leaves.

Blotches, also known as sprawling spots, are called the Tubakia Leaf Spot. These blotches usually appear brown to brown/orange and, on young trees, are well-defined and truly give a blotchy appearance. 

On older trees, the blotches may be larger. If these blotches are along the veins of the oak tree leaf, it could lead to a premature falling of leaves and also restrict water movement.

Much like the spotting on leaves, the best thing for Tubakia Leaf Spot here is to watch and monitor your oak, but also rake up fallen leaves, and prune branches for better air circulation and irrigation. 

Yellow, Brown, or Dull Green Perimeter on Leaves (Oak Wilt)

Ever see a leaf and notice it has a few different colors around its edge? Well, that is actually Oak Wilt.

Due to Oak Wilt, yellow, brown, or dull green perimeters on leaves can be an early sign of a distressed tree. This becomes a problem for oak trees because the leaves will drop too early, and in turn, will cause the tree to reach its end significantly faster as the leaves channel photosynthesis for the tree.

Oak Wilt is much more serious for Red Oaks. White Oaks are less susceptible to Oak Wilt, whereas Red Oaks often reach their end within four weeks of Oak Wilt first being spotted.

Oak Wilt is often caused by oak bark beetles in warmer temperatures. These beetles feed on their host tree and can introduce decay fungi which can create the wilt. 

The solutions to oak wilt vary depending on how intense the wilt is. Trenching is a solution that is used so that root grafting can be prevented. Sometimes, a trunk injection with a fungicide is used to stop the spread – however, this should be done and looked at by a professional.

Puckered Areas on Leaves (Oak Leaf Blister)

Oak Leaf Blister looks like the shape that any blister would look like, except it’s on a leaf! At the first sign of blistering, there may not be much of a color variation. The texture, however, will definitely feel bumpy – like many blisters on a surface. 

The longer the Oak Leaf Blisters are there, the browner they get, and the leaves can eventually curl and fall. Leaves are vital for the tree as they channel the process for photosynthesis.

However, this can be fixed.

The solution to Oak Leaf Blister’s puckered areas on the leaves is to simply watch and monitor and to keep the surrounding area of the tree clean. Continuously raking the fallen leaves and debris and throw the leaves out to prevent spread. 

Swollen Branches or Trunk (Crown Gall)

One of the most obvious symptoms of a dying tree is caused by Crown Gall. Crown Gall causes the roots, stems, branches, and trunk to look swollen and round. It almost looks like a big bulge on your tree. The Gall becomes the most troublesome when it is near the root crown, and at first, may seem spongey, but gets very hard the longer it’s present. 

The solution to Crown Gall on an oak tree is prevention and maintenance. Crown Gall is a bacterium in and of itself, and by making sure there are no open wounds on the tree and also by controlling insects, the bacteria will not be able to get in. Insects can carry Crown Gall and spread it to the tree. 

White Textured Spotting (Armillaria Root Rot)

White textured spotting, caused by Armillaria Root Rot, appears as a white, yeasty substance on the tree bark and branches. Caused by fungi, if your tree experiences this is can reduce its growth, have a premature leaf drop, and in turn, can cause the tree to reach its end significantly early.

Armillaria Root Rot can be hard to detect, as it usually is present under the bark of an oak tree. However, a sign that this is occurring in the presence of red to brown clusters of mushrooms growing at the base of the tree. 

The solution to Armillaria Root Rot is to try to increase the tree’s vigor and making sure the tree doesn’t experience any flooding. Proper irrigation and fertility (improving soil composition and nutrients) are key in doing so.

Peeling Bark (Phytophthora Root Rot)

Peeling bark, or simply put as Phytophthora Root Rot, should be managed quickly on an oak tree. If Phytophthora Root Rot is present, the tree will reduce in strength, and the leaves may start to turn yellow. Depending on how intense the rot is, trees can hold out for a few years but will have a significantly shorter span.

Phytophthora Root Rot is difficult to detect in oak trees as the roots are the main problem, and they are underground. The roots will turn a different red-brown color if they do have it. You may notice Phytophthora Root Rot near the stem of the tree underneath the bark as well.

The solution to Root Rot on oak is irrigation and maintaining a good soil drainage system. From the get-go, avoid planting trees too deep, as that can be one of the factors that attribute to Root Rot.

Of course, you can’t do much to change how deep your tree is currently planted. Just make SURE the tree has proper irrigation.

Mushrooms at The Collar (Heart Rot) 

Also known as Heart Rot, mushrooms at the collar of the tree are a no, no, and should be managed as soon as possible! 

When first spotting Heart Rot, you may see some white rot on the wood of the oak tree as it starts to become spongey as it decays. On the bark itself and collar of the tree, you will start to see mushrooms that can get quite large and will almost appear like it’s wrapping around the bark. 

A tree with Heart Roots can decline quite rapidly, as the branches will wilt away, the tree will lose its leaves, and when leaves are supposed to be green, they will appear yellow and brown. The mushrooms, however, will fall off within a few weeks once this happens.

The solution to Heart Rot is to time pruning when spores are not present. When the mushrooms fall off, or the spores are no longer present – usually in the colder months, it’s the perfect time to prune. 

Vertical Stripes (Hypoxylon Canker)

Vertical stripes seen on the bark and on the branches of your tree are a sign of Hypoxylon Canker.

The stripes on your oak tree will develop over silver-gray, tan patches and eventually will turn black with yellowing and wilting leaves also accompany this. 

The solution to these vertical stripes (Hypoxylon Canker) on your tree is prevention. Keeping a tree strong by ensuring proper irrigation is key. Making sure there are no wounds on the tree or insects, such as beetles. If you do see a wounded limb, removing it right away will help to refrain exposure of the disease to the rest of the tree.

Tiny Yellow Spotting (Fusiform Rust)

Tiny yellow spotting on the leaves and trunk of an oak tree occurs because of Fusiform Rust. The yellow spots almost mimic the idea of hair follicles and will have a hair-like appearance with a yellow to orange color. The spots are tiny, like pin-points, and are in clusters. 

Fusiform Rust may not be so noticeable in already planted and growing oaks – however, it is very common in a tree nursery. In order to prevent it, fungicides should be used in young oaks.

Initial Steps to Take to Prevent an Oak Tree from Dying

It’s important to understand what you CAN do to keep your trees full of life. The thing is, there are actual steps that you can take from the beginning that can prevent your trees from reaching an early end. If you know, you know, but if you don’t – we are here to explain! 

Additionally, you’ll want to plant your oak tree at the right time as well. This is quite crucial. Here’s our piece on when the best time to plant an oak tree is.

Pick the Right Oak Tree

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Old oaks in the fall by the pond.

Now, we know all trees are beautiful; that kind of goes without saying, but not all trees are meant to be in all climates. Although oaks generally do good in a mixed climate, there are specific oaks that you can choose for your area. 

If you need to pick the right oak tree, you can view our guide on the best oak trees to plant here.

Keep Grass Away From The Tree

Grass will actually fight the tree for air, water, and nutrients; thus, when planting a new tree, it’s a good idea to keep it away from a grassy area! In the early stages, a tree is at its most vulnerable, and it needs all the air, water, and nutrients it can get. Adding mulch around the tree is a much better alternative.

You can read our guide to planting oak trees in your backyard for more info.

Provide Plenty of Water to Your Oak

Depending on the soil drainage, your new tree will need water to grow to its highest potentials. It’s important to at least water your new tree every other day. For the first three years after planting, If the soil is dry, provide about 1-1/2 gallons of water per diameter inch of the trunk.

Remove Tree Stakes Early On 

This is the typical remove the training wheels idea. The only reason a tree should have stakes in the first place is if it’s too young to stand on its own. Once the tree has been planted for a bit and has the capabilities to stand on its own, the stakes should be removed. 

The trunk of the tree will grow much stronger if the tree has the ability to sway in the wind. 

Pruning Your Oak Tree Properly

New oak trees don’t need a ton of pruning. As the tree begins to grow, it’s important to look out for any low branches that may be growing, as if they get too close to the ground, pruning them would be a good option. 

Removing dead or damaged limbs or suckers that sprout from the trunk is always important in pruning a new tree.

Fertilize Only When Needed

With new trees, a lot of the time, you think fertilization is necessary – however, it can cause more damage than good if you fertilize when you don’t have to.

When the tree is first planted, it’s okay to add fertilizer, but after that, take a look at the tree and see how it’s looking. If it shows any signs that it’s unhealthy – then fertilizing is necessary. 

The Take-Away!

Trees are beautiful and are true sentiments to our outdoor scapes; however, like any plant, they need special care, especially at a young age, and can be prone to different diseases. 

The best way to stay ahead of the game is by prevention; however, if you ever do happen to notice an early symptom, don’t stress; there are ways to help your tree get rid of the disease and to live a long and full life.

References

Pearce, M., & Williams-Woodward, J. (2009). Key to diseases of oaks in the landscape.

Jung, T. H. O. M. A. S., & Blaschke, H. E. L. M. U. T. (1996). Phytophthora root rot in declining forest trees. PHYTON-HORN-36, 95-102.

“The Tree Owner’s Manual .” Northeastern Area State and Private Forestry, United States Department of Agriculture.

“Tree Planting.” National Association of Conservation District, nrcspad.sc.egov.usda.gov/DistributionCenter/pdf.aspx?productID=51.

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