How to Tell if a Tree Is Sick: Five Signs to Watch for

Trees are some of the most resilient living things on the planet. However, like any other living creature, they are prone to illness and could suffer severe consequences if left untreated. 

Fortunately, you can determine the health of a tree simply by keeping a close eye on it. 

This article reviews some signs of a sick tree that a certified arborist in Phoenix would look out for. These tips can teach you how to tell if a tree is sick and what steps you could take to alleviate the issues.

1. Leaves Turning Yellow Outside of Fall

When the leaves on your tree turn yellow outside of autumn, nutrient deficiency is typically to blame. Out-of-season yellow leaves are also known as “chlorotic.”

Chlorotic leaves on a tree can occur for various reasons, including:

  • Your soil is highly acidic with a low pH level.
  • There is a lack of nitrogen in your soil.
  • There are not enough minerals in your soil.

Properly fertilizing your trees is the best way to deal with yellowing leaves. Adding nutrient-rich fertilizers to your soil can give your tree the help it needs. 

2. An Abundance of Insects or Fungus

Pest and fungi favor living in material that is dead or otherwise weakened. When you see an abundance of insects or fungus on a tree, that’s a strong indicator that your tree is dead or dying.

If you notice fungi forming on the base of a tree, it’s a sign that your tree’s root system may be dead or diseased. 

3. A Leaning Tree Trunk 

While leaning isn’t always a symptom of an unhealthy tree, it’s something to consider. If a tree leans as it’s growing, it’s usually not going to be an issue. However, if a tree develops a lean later in its life, this can pose a serious issue.

When a tree has a lean of over 15 degrees from the center, it may result from damage from wind, insects, or decay. If a tree has a severe lean of over 30 degrees, removal will likely be your best option.

4. Parts of the Tree Are Dying

It may seem obvious, but when a tree is dying, it starts to lose more and more of its branches and look worse for wear. If you notice an abundance of dead branches on the ground, this is indicative of a dying tree. 

Losing branches doesn’t always mean a tree is dying, but it’s worth inspecting the tree when you notice it. Look for soft, decaying wood throughout the tree; this is one of the easiest ways to learn how to tell if a tree is sick.

5. Irregularities in Your Tree’s Bark

A tree’s bark is its first line of defense, so when it starts to look abnormal, that could be a problem.  Here are two primary symptoms you should be on the lookout for:

Loss of Bark

Like branches, a dying tree will often lose bark. If you notice areas of smooth wood where your tree used to have bark, you could have a dying tree.

Vertical Cracks

Any open area of a tree is prone to pests and fungal infestations. If you see one or more vertical cracks in your tree, it’s likely at risk.

Trees are an essential part of our yards, and there’s nothing more upsetting than needing to remove an old tree that’s been in your yard for decades. For more help on how to tell if a tree is sick or how to save a dying tree from lack of water, call our team at Tree Workers of Phoenix at 602-320-2797.


Tree Workers of Phoenix has been in business since 1994 and is a member of the Better Business Bureau (BBB) and International Society of
Arboriculture (ISA).


18402 N. 19th Ave. #115

Phoenix, AZ 85023

Phone: 602-320-2797

Email :

Hours of Operation :

Monday - Sunday : 9:00am-5:00pm


Call Now Button