Please do note the official warnings of the BFS (Federal Office for Radiation Protection). Contamination of forests with Caesium-137 is a health risk in many southern Bavarian forests. It's half-life period is 30 years. The disaster was in 1986. That means it's still roughly half of it there and the layered forest grounds preserve radiation well.
If you're a mushroom forager on vacation in southern Bavaria - just don't do it. Or at least inform yourself which types of mushrooms you shouldn't eat in particular for radiation reasons.