Bugs in my Oak..

[NatureBoy]

Howdy!
You folks know trees better than I, but I still love my trees.!

I live in NC and have an Oak tree in my front yard about two feet thick. At the base of the tree, by the "knees" are openings. Up in these openings are ant-like creatures (Haven't seen any winged). They are obviously eating the interior of the tree and I assume they are also in the ground. Termites?
How do I kill whats killing/eating my Oak? How do I properly seal the spaces between the knees? Will I be able to kill what's in the ground as well as in the interior of the tree?
Is there an "environmental" way of accomplishing what I want done?
I really appreciate any help I can find here..

Doug

 

[John Paul Sanborn]

If the formosan termite is in your area, get someone to look at it who can tell a termite from an ant.