Although I had been to the Heinrich National Park before, I stopped at the Grumsin area of the MAB Reserve in September 2017. Both are part of this Primeval Beech Forest WHS in Germany (as well as in 11 other countries).
A bus from Angermünde dropped me off right in front of the WHS Info Center in Altkunkendorf, but this 30 min. public bus ride that went around the most rural area I have ever seen in the state of Brandenburg was like a roller coaster ride and is highly recommended.
The couple at the Info Center was extremely helpful and recommended me to take a combination of two color-coded hiking trails in the area during the 5 hours I had there.
But the trails only go around the core zone, and the couple had told me that it was prohibited to walk into the core zone (as it is in the Shirakami Mountains Beech Forest WHS in Japan). Although I saw several trails that branched out into the core zone without any prohibiting signs, I didn't bother walking in, as all beech trees looked like the same to me.
But because I had only driven through the Heinrich NP, this leisurely hiking, breathing the O2 emitted by the WH beech trees, was a much nicer experience.