He told me, that are the cells of Sphagnum beotuk.

This orange lichen is perhaps a Caloplaca, that grows on N-rich places. So bones would fit.

I do not know lichens very well, but I think not. Some special mosses often do it. They (most Tayloria tenuis) sometimes was used in forensic to know how long a murder victim has been lying in the forest.

Yes, but not only Back Forest.