Give us a little information, please: where are you, and have you been using organic approaches to pest control? Do you garden with organic materials? What kind of trees are being cut, and how wide-spread is the ant problem. Are they in buildings as well, or just outside?
Ammonia isn't going to do anything any good. Please stop doing that.
Have you looked in Howard's
Library of organic information that includes lots of entries about ants? I won't link them all here, the hot link goes to the A page, scroll down to find ants.
There is a granular spinosad product that I've used for fire ants that has worked pretty well, but it sounds like your case is so severe that you need to give the area a good watering then put out an application of beneficial nematodes. Buy them from someplace that keeps them refrigerated and don't let them get too warm or let them freeze before you use them. You'll need to use them at the watering can strength, not the hose-end sprayer strength.
And now some food for thought:
Attachment:
File comment: This is a close-up of harvester ants entering a hole in a bit of a depression. The hole is in the Texas Canyon rest area in SE Arizona. Keep in mind that if you destroy the harvester ants you'll never have horned toad lizards on your property.
AZ-harvester-ants-1a.jpg [ 864.27 KiB | Viewed 9371 times ]
If you google "harvester ant" the results you get all are about horned toads. Why? They go together liked peanut butter and jelly.
Attachment:
File comment: This medium size image comes from the Wikipedia commons. Bear in mind - if you get rid of harvester ants on any property, you assure that no horned toads will ever live there.
640px-TexasHornedLizard[1].jpg [ 67.89 KiB | Viewed 9371 times ]