John Speese Apr 8, 2010:

I googled it and found quite a few hits for Bluteiche, most of which were some subspecies or cultivated varieties of Quercus robur, including the suggested atropurpurea and also fastigiata, which are the red oak and the columnar English oak, respectively. The phrase could mean "the only red oak or hanging oak variety/cultivar in Mecklenburg" rather than the only individual tree.

Cetacea Apr 8, 2010:

Different meaning Whether the species is Q. robur atropurpurea or rubra, I doubt that there's only a single one of those trees in all of Mecklenburg. "Bluteiche" does have a different, non-botanical meaning as well: It designates a "hanging (oak) tree"...