Luzandro
actually the first one who set something different than track was evod years ago to increase the importance of Vorwerkstraße / Saltenstraße: 
https://www.openstreetmap.org/changeset/33893656
Reiner changed parts of this back to track and parts to service
IMHO this all should be highway=track + tracktype=grade1
apart from the fact that it is signed as a forest road, there are also hardly any other tracks with grade1, so to some degree it stands out anyway