Hello, Marv.

Thank you for sending your questions to Ask a Master Gardener.

Your leaf photo appears to show an infestation of shothole leafminers that likely started earlier this spring. This common pest feasts on the leaves of a variety of trees. The larger hole size and dry, brown blotches indicate that its mining efforts have finished and these pests have moved on. This is typically a one-generation event and it's likely you will not see this damage again next year.

What to do: As bad as it may look, there is no need to spray or treat your tree. Shothole leafminer damage occurs only to the leaves. Research suggests that the tree itself is not harmed. There’s more on this here: https://bygl.osu.edu/node/1796

Additional reading and guidelines are here:

https://bygl.osu.edu/node/1576

https://content.ces.ncsu.edu/oak-shothole-leafminer

After zooming in closely on your tree bark photos, I noticed signs of lichens, a naturally occurring combination of fungi and algae. Lichens come in many shapes, sizes and colors and are found on trees worldwide. A wet spring may have fostered more lichens than usual and the wide bands and blotches could mean that your tree has hosted lichens for some time. They are harmless to your tree. 

https://ohioline.osu.edu/factsheet/plpath-gen-12

Lichens thrive in shady, secluded areas. To minimize lichen growth, the next time you prune, do so in ways that allow more sunlight to reach between the branches.

I hope this information is useful. Please be in touch if you have further questions.