Crack at base of oak tree

I just noticed this crack at the base of a Mexican White oak tree in my yard. The tree was planted last November and has been growing very well. It has put on 2-3 feet of growth since being planted and is up to about 12 feet tall. There is no yellowing of leaves. It all looks healthy except for this crack.

For some background, I live in San Antonio. We did have a bad freeze in February of this year with temperatures around 10 degrees. We have had a more wet summer than normal. Otherwise the tree has been fertilized regularly, and I cannot think of any other issues.

Any ideas as to the cause? If there anything that I need to do at this point? Is the tree in serious trouble?


1 Like

Looks like bark is developing ridges and groves. No damage

It looks like you have the mulch mounded up too high at the base. You want to see the root flare above the soil line and/or know the topmost roots are leaving the trunk right under the soil line. I’m not sure if that is causing a problem, but it is likely to over time.


Would agree with @zendog on not seeing the root flare. Hopefully it’s right under the mulch, because otherwise that could be bad. I have had a few spots like this on my monterreys that grow too fast. Just keep it clean, dry if possible, and should heal by late spring next year! Again, you really want to excavate down to the root flare on this pretty little bugger.


I would suspect south west injury ?
Is it on the south west side of the tree ?

Thank you all for the replies. I will be sure to remove some of the mulch. The mulch surrounding the tree is ~2 inches higher than the surrounding grass, so I should have plenty of room to work with.

Yes, the injury is on the southwest (mainly west) side of the tree. What is the significance of this direction?

Thanks again for the help!

South west injury is …
Splitting of the the bark on the south west side of tree trunks ,often near the ground. Lower portion.
This happens on cold clear winter days at sun set.
The bark on the south west side is heated by the sun just before sunset ( expands). Then with quickly plummeting temperatures the bark ( contracts ) cracks usually right at sunset.
I live in a forest , I can often hear the trees popping at sunset,
( loud pops ) on cold clear days , right at or just after sunset ,
Happens most often when it’s in the single digits, or lower .with clear sunny sky before sunset .
White paint on the lower trunk can help prevent this .