Question
We live in Washington and read your answer about thatching ants with interest as we have a large fir tree in the back yard with the ants going up and down the tree but they seem to live under the tree as it is built up in a huge hill around the roots and under the tree.  The tree is huge, about 60 ft tall,  does this loosen the trees roots so that is in danger of falling in a storm?

Answer
No the ant bed at the foot of a tree this large will have no effect on the stability of the tree and the root system. I would check with your local nursery/garden type store and buy an ant bait insecticide and treat the mound. The advantage in using baits is that foraging ants take the insecticide back to the nest and feed it to the queen(s) and other colony members. As a result, the entire colony often is destroyed. Ant bait products currently available include Amdro? Amdro?Fire Strike, Extinguish? Extinguish?Plus, Distance? Green Light? Spectracide? Ferti-Lome? Advion? and etc. Baits are slow acting and require weeks to months to achieve 80% to 90% control.