Von Eichen sollst du weichen ...

The final lies on private ground. The owner has approved the search but not the entering of the grounds, which is not necessary at all.

The chase begins at the coordinates given. If you can't find a parking space you can try in the street below; but on certain afternoons in July and August you'll be in for quite a walk. Public transportation available: Bus line 9 to "Gontardstrasse" on work days, line A to "Gartenstadt" on sundays.

Back to stage 1: You will admire a line of stately oaks but will also notice some obvious numbers:

white: A b C D
yellow: E F
black: G

Those numbers will lead you to Stage 2 at

N 49° 57.b + D*2,5 E 011° 34.A+C+D+2*F+G+1

Please mind operator priority and the parens.

From there you can see another stately line of oak trees. Keep looking for some less obvious numbers, though:

H
I
J
K
L

Now go (as near as possible without actually entering the shrub) to the point in the middle between oak #L/2 and oak #H (from the right). (Stage 3).

From there go

2*K-H metre in direction K + J/(H+I)°

and lo! you'll stand between two oak trees again. You have not reached the final location yet!

If you know some german lore, however, you'll be able to spot the final location quite easily.