Why are you so terrified of the Black Forest raid? It's just a bunch of greydwarves that you can mow through easily. The raids are also extremely rare.

You're massively gimping your progression by putting off the ability to mine ores for no good reason.

To answer your question, raids only trigger based on boss kills. While a troll is way harder than the first boss, killing one won't have anything to do with raids.

EDIT: Looks like I was wrong on the troll not mattering, as the guy above said you need to kill Elder and at least 1 troll for troll raid to happen.