Pink, I kinda skimmed along and didn't read every word. If I repeat any thing sorry. The fungus is a sign of internal rot. Others stated you should see how deep the rot is. A tree only grows from the outside. No matter how healthy it is it will not grow new heart wood and be structurally strong again. The life of the tree is in the cambium just under the bark. As long as it has a healthy cambium it will continue to grow up and out. Making it heavier and more likely to split. Cabling the limbs might give them some support. But, in a heavy wind, that big sail could twist the trunk in half, and there is no real way to support that. If you would like to see a real GIANT that had many of the same problems that your tree has google "Marylands Liberty Tree". It was a 4 hundred year old Tulip Poplar. I saw it just a few month before it came down, it was amazing.
I understand your wanting to save this guy. You just have to realize that you can keep it externally healthy. You can feed it and pamper it and prune it, and it will continue to get taller, and have nice big healthy leaves. But, all of a sudden it'll just collapse. The trunk won't be able to support the weight of the crown.
If I had a tree like that on my farm I'd leave it, and enjoy it, knowing one day it will collapse. If it were anywhere near people you have to consider their well being.
Another thing to be weary of, in your desire to "Help" your tree, don't "Harm" it. The back fill was done 50 years ago, the tree adapted. When you cleaned the fill soil away you scored up the roots pretty bad. The root damage with all of it's other health issues didn't "Help" it. Now it has to divert energy into healing the root damage that could have gone to callus tissue in other parts of the tree. Just doing stuff to the tree doesn't mean you are helping it. If you had a 16 year old Lab would you put it on a leash and make it run a mile? Running is good exercise. No you wouldn't. Some times just leaving it be, and making it comfortable, is the best thing you can do. Good luck with the old guy, Joe.
I understand your wanting to save this guy. You just have to realize that you can keep it externally healthy. You can feed it and pamper it and prune it, and it will continue to get taller, and have nice big healthy leaves. But, all of a sudden it'll just collapse. The trunk won't be able to support the weight of the crown.
If I had a tree like that on my farm I'd leave it, and enjoy it, knowing one day it will collapse. If it were anywhere near people you have to consider their well being.
Another thing to be weary of, in your desire to "Help" your tree, don't "Harm" it. The back fill was done 50 years ago, the tree adapted. When you cleaned the fill soil away you scored up the roots pretty bad. The root damage with all of it's other health issues didn't "Help" it. Now it has to divert energy into healing the root damage that could have gone to callus tissue in other parts of the tree. Just doing stuff to the tree doesn't mean you are helping it. If you had a 16 year old Lab would you put it on a leash and make it run a mile? Running is good exercise. No you wouldn't. Some times just leaving it be, and making it comfortable, is the best thing you can do. Good luck with the old guy, Joe.