If trees with black bark are observed chances are they are facing complications like fungi attacks, bacterial diseases, and insect infestation.

Trees With Black Bark

Barks also turn black due to trees’ natural response to different stresses, like improper pruning, woodpecker attack, etc.

If you want a complete explanation of these causes and easy ways – pruning, keeping your garden clean and so on – to deal with them, stay ‘til the end.

What Are The Reasons Behind Trees With Black Bark?

Tree bark that changes color to black is mainly because it is infected by fungal and bacterial diseases. Also, when an insect attack is underway, the bark starts having black patches. Furthermore, natural responses and genetics decided by nature also lead to darker barks.

– Fungal Infection

A fungal attack is one of the main reasons tree bark turns black. It usually occurs when you apply more water, the soil has poor drainage, and when humidity levels are high. So, which fungal diseases cause barks to look black?

Verticillium wilt is the leading disease caused by the soil-borne fungus Verticillium dahlias. In this disease, the vessels that carry water are affected. As a result, water and nutrient uptake don’t occur properly, and the bark will eventually turn black. That’s not all. You will also see fungal spores on the bark, which will make them appear black as well.

In addition to Verticillium, the other fungal bark disease is black knot. Steganosporium Ovatum fungus is the main reason it grows within the tree and infects inner tissues. When this happens, knots and galls are formed on the bark. Due to this, the trunk gets swollen and becomes black.

– Bacterial Diseases

When you don’t keep the surroundings clean, bacteria will build up and eventually attack the trees, causing barks to change their appearance to black. Fire blight is one such disease that is caused by Erwinia amylovora bacteria.

This disease usually attacks fruit trees, but others are also not safe. In this disease, barks start turning black, and shoots start to wilt. If the attack gets severe, the whole tree can die too.

Furthermore, trees also face bacterial cankersis. This bacterial infection usually damages older or weaker trees. In addition, bacterial wetwood is another bacterial disease that makes trees appear black. Trees affected by this ooze a black liquid that covers the whole bark. That is why you will think that the barks have turned black.

Reasons of Trees With Black Bark

– Response to Stress

Tree bark can also start having black patches when there is any stress. For example, when there is a storm, the barks can get black because of their impact. The common thing that causes “black bark response” is pruning or cutting the bark. Trees release sooty mold in this situation, giving barks a black or darker look.

Similarly, when small woodpecker birds peck the bark, sooty mold is excreted too. Usually, the growers of maple, pine, and elm face this problem. In addition, more than a dozen other species can also excrete molds.

– Natural Causes

Some trees, like black locusts, birch, etc., naturally have black bark. So, it is completely fine for them to have a darker bark. Those who are beginners or haven’t grown trees often get concerned about the bark color, but there’s nothing they can do about it. It’s genetics. The black birch tree naturally has brown to black bark, while the black locust has reddish-brown to black.

However, note that black birch bark is prone to environmental stress. So, if you are growing this tree, you should check the insect infestation and look for any signs of diseases. For this, make a habit of checking bark and leaves frequently.

– Insect Attack

When your tree’s bark looks black, then chances are it is attacked by insects. Bark beetles are a common one that makes tunnels in the bark, causing them to look black. Ambrosia beetle is another insect that loves to burrow into the bark and change its color.

Furthermore, carpenter ants also love to feed on the bark as well. You might find scale insects on the trees too. They love to suck sap, which leads to trees turning black. Usually, maple growers face the trouble of insect attacks. You already read how they feast on the bark. That’s only one thing about them. Insects also leave sooty mold on maple trees, making them black.

So, if you see a maple tree trunk turning black, look for insects nearby, as they are the main culprits. Want to know how to treat black bark on a maple tree (or any other tree species)? Then continue reading.

How to Cure Black Bark on Trees?

You should follow best cultural practices to treat black bark and cut off infected parts. After this, clean your garden. Then apply fungicide when there is a fungal attack, apply bactericide in case of a bacterial attack and spray insecticides in the insect infestation.

– Follow Appropriate Growing Practices

When barks turn black, the first thing to do is to follow the best cultural or growing practices to control disease spread. They are also crucial because other solutions depend on them too. What are they?

  • You should check the soil’s moisture condition and decide when to apply the water. It is because over-adding can promote fungal growth.
  • Similarly, it would be best to cut the extra shoots to improve the aeration. When more air passes, the humidity levels get controlled.
  • Also, if you see eggs or larvae in the soil, remove the top layer and replace it with a well-drained one.
  • Add compost, manure, and organic matter to improve soil drainage capacity. Doing these things will keep the fungi and bacteria attack in control.

– Prune off Infected Parts

Another effective strategy to stop disease spread is to prune off the infected branches, shoots, or leaves. When you cut them, fill them in a bag and dispose of them far from the trees. Don’t bury them in the growing site, as it will worsen the condition.

Solutions of Trees With Black Bark

– Keep Garden Clean

Bacteria and fungi accumulate in your garden when you don’t clean it properly. So, you should clean the pet’s feces, pick up dropped leaves, and pull out dead plants. You should also make sure the garden beds stay debris free too. Also, don’t let water “spill” everywhere in the garden. Apply it carefully to avoid facing this problem.

– Apply Fungicide and Bactericide

When fungal and bacterial diseases get severe, it is better to use fungicides or bactericides. These are easily available online and in gardening stores. When you are about to apply, read every instruction printed on the label carefully to avoid further complications.

– Use Insecticides

To deal with harmful insects, get help from insecticides. First, spray the bark with neem oil or insecticidal soap. You can also try cayenne pepper spray for this purpose as well. If organic insecticides do not eliminate all these unwanted creatures, then go for chemical insecticides. These will kill all the pests, providing trees relief and time to recover from their attack.

Conclusion of Trees With Black Bark


So, that’s all about what causes black bark in trees and what you can do to cure this problem. Here are the key takeaways of the article to refresh every important detail in mind:

  • To deal with fungal and bacterial diseases, prune off infected parts and apply appropriate fungicides and bactericides.
  • In case of an insect attack, apply organic insecticides like neem oil, insecticidal soap, cayenne pepper spray, etc.
  • When you still see some insects, then try chemical insecticides.
  • Always keep your garden clean to avoid different tree complications.

That’s everything about reasons and solutions for trees having black bark! If your trees have brown leaves make sure to read our guide and cure them.

5/5 - (5 votes)
Evergreen Seeds