I do not know how many years will live a young tree.
But I know that in this moment - they are together and they cherish each other ... and if a young tree grows on old tree, it means that the old tree is alive! :)
The cycle track is in the hilly Weserbergland. Because the way is a previous railroad line, you can bike through the hilly scenery without climbing a rising slope. - very well for weak cyclists! :-)