11 Symptoms of a Sick Tree

If you notice a foamy fluid coming from your tree, it may be alcoholic white flux. In extreme cases, excess fluid will pool at the base of the tree. White flux will commonly set into trees stressed by drought and heat.

This fluid often has a fermentative odor and leaves dark streaks down a tree’s bark. Most trees with alcoholic white flux begin to produce fluid in spring and summer.

Fire blight can affect pear trees, apple trees, and some other members of the family Rosaceae. The shoots or flowers on the tree turn black and shrivel into the shape of a shepherd's crook when a tree has fire blight. 

These symptoms typically appear only a few weeks after a tree has been infected. This is a fast-moving blight that has been known to wipe out an orchard in a single season.

Inonotus dryadeus is an inedible fungus that causes white butt rot and root rot in oak trees. 

This fungus forms near the soil. It has a lumpy, irregular cap with a dull yellow surface that exudes droplets of amber liquid when fresh and young. It has a beige pore surface that ages brown, Over time, the fungus hardens and turns black.

Infected trees could fall soon after showing obvious symptoms, so you should have the tree removed if you see signs of this fungus.

Yellow and brown leaves, along with slowed tree growth are signs your tree has armillaria root rot. You may also notice excessive wilting and major branches dying in trees with this disease. 

Fungus in the soil attacks and rots the roots of plants and trees, causing them to fail.

Trees with armillaria root rot may take a few seasons to die. However, this process will accelerate if the tree doesn’t receive enough nutrients or has attracted excessive amounts of insects.

Another common sign of disease is a white, powdery substance on the leaves of trees. This is powdery mildew, and it will usually develop later in the season when the weather has reached high humidity levels. 

Along with white mildew, you will likely see a distortion of leaves and stunted tree growth.

In the early stages, powdery mildew starts in small, white spots. These spots will expand and eventually cover the leaf’s surface.

If you see this happening, call a professional arborist immediately. Diseased trees should be treated quickly, or the tree may die. If you happen to use the wrong treatment, you could accidentally kill the tree. 

The biggest giveaway of a sick tree is bare branches during the seasons in which they should be covered in leaves. 

Keep in mind leaves that died with a branch will continue to cling to the branch well into the winter instead of dropping to the ground as they would on a healthy deciduous tree.

Some common signs of infestation in trees include the following: 

• webbing nests
•  chewed leaves
•  fallen healthy leaves
•  defoliated branches
•  larvae actively consuming foliage
•  mottled foliage
•  hidden infestations under leaves
•  scale insects along twigs or branches
•  sawdust on branches
•  trunks indicating wood boring insects
• holes in tree parts.

You will undoubtedly have a hard time determining if a tree’s roots are damaged since they are hidden underground. 

Because they are underground, roots are less vulnerable than other parts of the tree in that they can’t be buffeted by winds or gnawed on by fauna.  

However, if the roots are exposed, they are vulnerable to damage from lawn equipment, such as your lawn mower or weed eater. Also, if you've recently done any construction projects near your tree, there’s a good chance that the roots were affected during the operation. Soil compaction and excavation that causes root damage is a common reason for trees to die. You need to ensure this hasn’t happened.

Another thing to watch for are small branches sprouting from the base trunk of the tree. Sucker limbs are the tree’s attempt to grow more branches, usually in response to injury. If the roots are damaged, sucker limbs will grow from the base of the trunk. If sucker limbs grow higher on the trunk, they’re usually at the site of a pruning wound, a crack, or some other damage.

Usually, as trees age, they replace the outer layer of their bark with a new layer, but if the tree’s health is declining, it won’t be able to regenerate the stripped layer.

If you have any trees showing signs of decay and instability, they should be removed as early as possible. Stories of entire trees falling into a neighbor’s yard aren’t uncommon, so that’s something you need to keep in mind.