Want to save burned out Oak Tree

[drmanny3]

There are two Oak Trees that suffered from the Tea Fire in Santa Barbara back in 2008. One of the trees has a very large cavity that must be around 4 feet by 2 feet. What can I do to preserve this tree. I have had the trees trimmed to lighten their load. Both trees appear to have healthy growth. I am concerned that in the wind the trunk will twist and the tree will self destruct. The other tree also has a burn cavity but not as large as this one. Looking for some ideas on how I can save them both. I understand that concrete was an old technique that is no longer recommended. What about construction foam and then wrapping the trunk with window screen material?
Thank you for any suggestions
Manny Fernandez, Jr.

 

[ATH]

Foam guarantees that it will never dry out - which is a great way to accelerate decay. It may fill with some water during the wet seast now, but dries in yet heat, right?

Leave it open. There is a balance between taking some load off and taking away 'food factories' that the tree will use to grow more wood around the wound. So don't get too crazy with pruning.

If the trees fall, will they hit anything? If they will, probably worth having a Tree Risk Assessment Qualified Arborists out to evaluate the extent of strength loss and probably of failure.