Frost rib

Asked October 14, 2018, 8:15 PM EDT

Our community has several oak trees that have an external vertical rib running from the basal region upwards. Someone told me they were frost ribs and others canker rib. I can only find little literature on this subject. Some are up to 4-5 feet in length. Most appear like a bulging rib under the oak bark of the trunk with no splits. The trees are at least 10 years old. I cannot tell if they are harmful or not. Can you enlighten me or suggest studies/reports I may be able to access.

Queen Anne's County Maryland trunk oak tree frost ribs

3 Responses

Please send us photos of the tree and affected trunk areas so we can see what you may be dealing with.


Attached are photos of the "ribs" on our pin oaks. On one tree there is a clear ooze coming from the rib. The bark on the ribs is held fast to the tree and there are no noticeable lesions or cracks.


There could be several reasons for bark splitting on trees. These look like growth cracks. Others types of bark splitting include frost cracks and sunscald.
No control is necessary. Keep the trees well watered during dry periods. Make sure mulch is no thicker than several inches and away from the base of the trunk. Here is more about them on our website and Cornell.

The clear liquid you are referring to sounds like slime flux. Here is more about it