Oak Tree Wetwood or Slime Flux Description, Causes, And Treatment

| |

We received this question in our article on oak tree diseases:

Our oak trees have been recently manicured.

We were concerned with cracks/openings near the bottom of the tree that seem to seep out really stinky, muddy leaf filled water. I use a stick to clean it out the best I can, but the liquid that comes out is super thick, stinky and black.

The arborists didn’t seem concerned, so maybe we don’t need to be, but I just don’t want it to rot from the inside.

Should we be concerned?

The situation might indicate a condition known as “wetwood” or “slime flux.”

This occurs when bacteria infect the tree, causing the tree’s fluids to ferment and create a foul-smelling liquid that oozes out.

What is Wetwood/Slime Flux?

oak tree slime flux wetwood
Image: @usuextension


Wetwood is typically caused by bacteria that invade the tree through wounds or natural openings. The bacteria ferment the tree’s sap, producing gases and liquid that ooze out.


Affected trees may have a dark, foul-smelling, slimy exudate coming from cracks or wounds. The liquid is often dark and thick.


While it can be unsightly and unpleasant, wetwood generally does not seriously harm the tree. However, it indicates that the tree is under some form of stress.

Potential Concerns

Structural Integrity

If the tree is heavily infected or has large cavities and structural weaknesses, there could be concerns about the tree’s stability.

Health of the Tree

Prolonged stress can weaken the tree, making it more susceptible to other diseases and pests.

Management and Treatment

slime flux pictures
Image: @lallemandforestry

Improve Tree Health

Ensure the tree is well-watered during dry periods and avoid additional stressors like excessive pruning.

Avoid Wounding

Minimize wounding the tree to prevent further bacterial entry.

Keep Area Clean

Remove the oozing liquid and debris regularly to prevent attracting pests and to monitor the condition.

Inspect Regularly

Regularly inspect the tree for any changes in the condition or signs of other issues.

When to Seek Further Help

Significant Decline

If you notice a significant decline in the tree’s health, such as leaf drop or dieback, or if the exudate becomes more severe.

Structural Concerns

If there are large cavities or concerns about the tree’s structural integrity, consult with a certified arborist.

While the arborists didn’t seem concerned, monitoring the situation closely is always good. If the problem persists or worsens, seeking a second opinion from another certified arborist may provide additional peace of mind and recommendations for treatment.


The STIHL Excalibur Chainsaw used in The Texas Chainsaw Massacre III

STIHL MS 211 Chainsaw Reviews: How It Compares With The MS 181 And MS 251


Leave a Comment