Be gone with it

Some of it could be cicada damage & might be slowly recoverable. But older pin oaks often do not age well -- in fact, that might be oak wilt. I'd at least wait until next year to see if it improves. If not.....

The tree is on a property border between me and our local government. The property line goes through the middle of the tree. I'm going to report the tree as a health hazard. Maybe they'll cut it down for me.

Cicadas wouldn't have caused dieback of a majority of the crown including larger limbs as shown in the photo. "Prior to this year, the tree was full of leaves and healthy ..." If it was oak wilt you probably would have noticed leaves browning and falling last summer. Difficult to tell from the photo whether the branches are dead, or perhaps just defoliated this spring - is there possibly an outbreak of fall cankerworms in your area? If significant sudden dieback has in fact occurred, that would more likely indicate a recent root/soil issue - was there any grading or digging done in the root zone?

What L Clark said.

I got out my binoculars and got a good look. I think the branches are dead. I don't see anything resembling leaf buds. Some of them might have died last year. Some have fungus growing on them.

Cicadas kill the thin stems at the cane ends. The tree was devastated by them. The tree was heavily covered with dangling dead branch ends. Maybe the tree was in decline and the cicadas pushed it over the edge.

Imagine 3x the damage in this image...

https://bygl.osu.edu/node/417

If those branches are dead, then L Clark and callirhoe's comments apply, and as you said, the tree was likely "in decline" already. It's true that cicada damage would have caused additional stress, but there were more serious issues at work prior to that.

From https://bygl.osu.edu/node/1773 - "Keep in mind that periodical cicadas co-evolved with their hardwood hosts. They are not tree-killers. Their oviposition damage to established trees is minimal."

tree is on a property border between me and our local government. The property line goes through the middle of the tree. I

==>>

was there any significant grading or work done on city property.. distributing half its root mass???

ken

The only recent change was I built a raised bed that was maybe 15' away this spring. It covers a maximum of maybe 5% of the root area. I have 30' tall arborvitae much closer and they're fine. I don't see how it could kill specific branches and not cause damage everywhere. I've done many things like this in the past and it never caused widespread damage to a mature tree.

On Friday, there was a government dump truck parked in front of my house. I don't know what they were doing. Maybe looking at the tree? it was pouring rain, so I didn't want to see what they were up to. I read my legal rights on the internet and they stated once a tree is known to be dangerous, the owner(s) are legally responsible to solve the issue. So hopefully this will force an action. I would be willing to pay half the cost.

The government guy came by this morning. They'll cut it down for free on Friday. Hooray. I offered to pay half. He laughed and said my tax dollars pay for it and they don't even have a way of splitting the cost.