Why Is My Tree Trunk Turning Black?

Taking care of trees comes with a fair share of responsibility. This includes inspecting the trees every so often for signs of deteriorating health. If you’ve ever asked yourself the question, “Why is my tree trunk turning black?” keep reading for more insights into the issue.  

In this post, we delve deeper into the reasons tree trunks turn black, as outlined by the best tree removal service in Girard, OH.  

What Causes Trunk Blackening?  

Tree trunks turn black for various reasons. The most common culprit? Tree diseases from fungi attacks, bacterial infections, and insect infestation. Your tree’s trunk may also turn black as a natural response to stress, like improper pruning.   

Common diseases that could cause your tree trunk to turn black include:  

  • Verticillium wilt  
  • Bacterial wetwood  
  • Sooty mold  
  • Black knot  
  • Bacterial cankers  
  • Fire blight  
  • Gloomy scale  

Pinpointing the disease your tree has depends on factors such as the symptoms and tree species. 

Fungal Infection  

Trees develop fungal infections primarily because of poor soil drainage, excess water, and high humidity levels.   

Verticillium dahlias, for example, the fungus responsible for causing Verticillium wilt, affects the vessels that carry water throughout the tree. This influences water and nutrient uptake, eventually turning the trunk black.  

Bacterial Diseases  

Poor hygiene around trees creates the perfect breeding ground for bacteria that eventually attack trees, causing barks to turn black. One such disease caused by erwina amylovora bacteria is fire blight.   

Another common tree disease, bacterial wetwood, makes trees appear black as well. Trees affected by bacterial wetwood ooze a black liquid that covers the whole bark, giving the impression that the bark has turned black.  


Did you know that trees succumb to stress? When asking yourself the question, “Why is my tree trunk turning black?” you probably never thought about stress as a possible reason for the tree trunk turning black. 

A stressed tree may develop black patches on the bark, say, after a storm’s impact, which could eventually lead to a dead tree top if the stress is severe enough. Improper pruning or cutting the tree bark may also cause the black bark response. 

Insect Attack  

If you notice your tree trunk turning black, insects may be to blame for your woes. Insects you want to look out for include:  

  • Bark beetles  
  • Carpenter ants  
  • Ambrosia beetle  

How to Deal With Black Bark on Trees?  

The best way to address a tree trunk turning black will depend on factors like the tree species, type of disease, and the level of disease. Following appropriate tree-growing practices goes a long way toward keeping your trees healthy and avoiding health issues.   

Some remedies to consider when you notice your tree trunk turning black include:  

  • Prune off infected parts  
  • Apply bactericide and fungicide  
  • Use insecticides  
  • Keep your garden clean  

When to Call a Professional  

The earlier you deal with structural defects or symptoms of declining tree health, the better. Proper care and maintenance will save you from spending plenty on an issue you could have avoided.  

However, don’t hesitate to seek professional help as soon as you notice an issue with your tree. Prompt action could be the difference between saving your tree and having to cut it down.  

Contact Your Local Tree Experts  

If you need professional tree care delivered by local experts, look to Starwood Tree Service to evaluate your needs effectively and provide exceptional tree services. We proudly serve residential and commercial property owners as well as forest landowners across the Greater Girard, OH, area.  

Our full range of services includes:  

  • Tree removal  
  • Tree trimming and pruning  
  • Stump grinding  
  • Land clearing  

Contact us at (330) 231-5022 for more answers to the question” Why is my tree trunk turning black?” or to learn about tree-cutting mistakes you want to avoid.  

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