Help with this oak

[Tree Tastic Care]

Had a look at this oak and fount these . What's best to do ?

[Gary Prentice]

I can't make out what the photos are meant to be illustrating.

There's a lack of development between the buttresses in the 2nd pic. Maybe due to a damaged root in the past, although the adjoining buttresses seem to be well developed and are probably compensating. The block paving circle has probably caused some damage too.

 

The cavity is, well, a cavity. A large wound in relationship to the parent stem, but it's in oak which has resistant heartwood. You'd need to be climbing up there to get an idea of its size before making any decisions.

 

Has it had a big limb/stem removed above the bird box, to the left hand side? 

 

What's your concerns?

[Tree Tastic Care]

The second photo when you tap the bark it's very hollow . But didn't know if the heartwood would be compromised by it making it not so much unsafe now but in future ?

[treeseer]

The hollow is in a sinus which is normal.  Soil replacement there might improve codit, and future health and stability.

 

As for the amputation wounds, really unfortunate.  Soil improvement will help that too.