We do see what appears to be rotting wood on the lower right side in your first photo. Smooth patch is a fungal disease that can cause whitish depressions in the bark of oaks, but from what I can see in your photo, it looks like this is deeper into the bark. The crown of the trees is also showing symptoms of thinning, an indicator that the tree is in the early stages of decline. A rotting area like this could have been initiated by a physical wound to the trunk or root. 

We do not make onsite visits to do tree health assessments. We recommend that you consult with a certified arborist. An arborist will have the tools and training to assess the extent of the internal decay and can assess whether pests/diseases are present. If boring beetles are present in the tree, there is little you can do at that point, unfortunately.

Sadly, many mature oak trees are in decline in various locations in Maryland. Some contributing factors are described in the following articles: 

https://extension.umd.edu/resource/why-oak-trees-are-declining-or-dying

https://extension.umd.edu/resource/browning-and-defoliation-white-oaks

Again, we recommend consulting with a certified arborist as the next step. You can find an arborist using this directory: https://www.treesaregood.org/findanarborist/arboristsearch.

Christa

Christa

Yes, your photos are helpful in that they do suggest a wound to the tree in the past, and some soft-looking rotted wood.

You can see by the round-edged callous tissue (on left in your first photo) that the tree attempted to heal over the area without success as it doesn't look visible on the other side of the area, and the soft wood is apparent.

A good certified arborist will be able to take all conditions into consideration and let you know how to proceed.

In the meantime, this page helps you to assess when a tree is in decline and when it may be time for removal: https://extension.umd.edu/resource/how-do-you-decide-when-remove-tree

Christine

Christine

Thanks for your prompt response. FYI I now have an appt with an
arborist from Bartlett
Monday morning.  Nevertheless this preliminary discussion is useful for me.
I was going to point out the round-edged
wood in the photos, but I didn't know what to call it so I'm glad you
noticed it.
There is something similar on the right side (note top of right side photo)
but without more "excavation" I can't tell if it extends all the way
to the ground -
but I suspect it does because the rotted section does seem to end on
that side also.
I have been in the house for 24 years and don't recall an injury but my guess
is that the tree is at least 100 years old - so
who knows what may have happened a long time ago.





On 9/17/21, Ask Extension <askextension> wrote:
></askextension>

Good. Good luck with Bartlett.

If you look around you might notice in a tree where a limb has been removed, the callous tissue begins growing from all sides, eventually meeting, covering and compartmentalizing the wound completely. 

Yes, it is difficult to know how it happened. It was likely a good time ago, and perhaps even another tree falling and slicing off some bark there.  The arborist should be able to assess the structural integrity of the tree for you.

Christine