Hi, 

The rings could be a wound from old sapsucker damage. Sapsuckers are a type of woodpecker and they will drill small holes in a line into the trunk of trees to get to the sap. Maybe the bark healed like that up the tree. It doesn't seem to be effecting the health of the tree though. 

The leaves have anthracnose symptoms which is not a concern. It is a common fungal leaf spot that many shade trees can get during humid weather in the summer. The leaf drop could be that or some minor drought stress. No treatment is needed unless you can supplement water in times of drought, that may be helpful. 

Other than that, if you have other health or safety concerns from it being a large tree and the potential for falling, we would recommend you contact an arborist to evaluate the tree and see if they have any recommendations. You can always refer back to us with their report for further guidance as well. 

Let us know if you have further questions. 

Emily