Last fall, we moved into a house in the Twin Cities area, MN. Zone 5A. There is a Bur oak that has minimal foliage - the foliage that is there is small and curling. Last fall, the minimal foliage was on a different branch on the tree compared to this year, where it’s mostly on a different branch. Some of the leaves have recently started to brown. I know it’s a long shot, but it makes me incredibly sad to see such an old oak tree be diminished to this when a few years ago, things could have been done to help its survival. 

Last fall and this spring, I have had two Arborists come out to look at this tree and other large old trees that we have (39” Bur oak, 45” and 42” silver maples). 

Over 2 months, I have dug down 16-24 inches to expose the root flair and to remove dirt up against the large rotting spot at the base of the tree. 

I have had a company come out to inject root stimulator into the soil because why not?

In the future, I will have an injected Two-lined Chestnut Treatment done and this week I will be doing a soil sample. 

I was considering NeemMax to spray on the tree to reduce any pests.

There is a hollow spot in the tree. Do I remove the debris and add some Sisal rope to wick any water out? 

The only fungi that I have seen grow on the tree was Chicken of the Woods (Laetiporus sulphureus). Unsure if there is root rot from the Armillaria fungus. There are a few small white spots on that rotted spot at base of tree. 

Is there any suggestions I can do to try to keep this tree alive? 

≈4ft in diameter Bur Oak issues