Dominion 2L is labeled to use on trees to help protect against boring beetles. Treatments should begin in May or June and should be done every year to protect trees from the Emerald Ash Borers.
Dominion 2L contains Imidacloprid which could indeed be harmful to honey bees. According to the Dominion 2L product label ,"This product is highly toxic to bees exposed to direct treatment or residues on blooming crops or weeds. Do not apply this product or allow it to drift to blooming crops or weeds if bees are visiting the treatment area."
You may want to consider using ant bait in a bait station such as the Ant No More Bait Station which can be placed around the base of the infested trees. By placing the bait into the station you will be protecting it from the elements. Ant No More allows you to add two of your own favorite liquid, gel, or granular ant baits. The choice of two different baits ensures greater attraction for all kinds of ants.