Pecan tree help

[Pyewacketcat]

I have a really old ,probably 40+yr old pecan tree over my garage and house,it has grown into the fence. I have just noticed a white foamy substance at the base of the tree,and I am wondering what it is,if I need to do anything for the tree... I don't want to lose the tree.
A friend said she had some thing like it at her house,and it killed several of her trees.
Anyone have any ideas on this ?

 

[treeseer]

Pecans can get bacterial infections; see attached. It's a sign the tree is in trouble, but that trouble is usually manageable.

Posting a picture will get you much better advice!