To solve this simple puzzle, go to the place indicated by the coordinates with the puzzle picture. There, you'll be able to guess the answer to the question, and having X: YZ you can decrypt the final coordinates of the woodpecker hollow:
N 51° 59.(X+X+1)(Y+Y-1)(X+Y+1)'
E 20° 21.(X-3)(X+Y+Z-2)(X+1)'
(puzzle picture: 1200px)
When you find the right tree hollow, please take the container carefully so not to destroy it.