Lokalfuerst
Hello fellows,
i did read all the comments at the time and found it (unsolvable) difficult to find a proper tagging for the usual (German) "Waldweg". The difficulty is that the signs that partly display the access mode follow certain old rules, that are in reality not being followed hardline. For example if the sign sais no  motor cars, but the forestry worker claims, that he had to go that way for certain reason he will not be brought to justice. Bicycles and foot are usually always allowed on the ways (if not forbidden and not tagged..) ; even if it is called 'private property' for some Grossgrundbesitzer, the access is tolerated alt. it can hardly be explained to indivucuals entering the way for what acceptable reason they shall be prohibited to go. The before mentioned tages motor_vehicle = forestry;agricultureal seems to cover most needs, covers the for the forest sensible motor_vehicles and leaves other options untouched. For the tagging access=destination there is the question about what is a legitimate destination. If a destination is a node where to start a walk (Spaziergang), it will be less accepted than if a 'Förster' goes to sit on the 'Hochstand' in the morning hours. For my sense 'destination' opens too many doors. 
OK, my words are not the final solution, but maybe they do highlight a bit the involved parameters. For my part i did so far not or rarely tag access for highway tracks for the fear to generate unpredictable results in routing.  
If anybody has by now stronger suggestions abotu this, it would be nice to hear about it.
Happy mapping!