I am regularly fascinated by the way in which a fallen tree will be the source of food for new plants.  The decaying wood releases nutrients and provides a great base for the next generation.  Of course, as it decays further, the base may gradually disappear from under them.  In the interim, though, any number of plants will sprout and develop.  I came across one such log in Meerkerk Gardens.  It seemed to be home to any number of new plants (and that ignores the insect species that were, no doubt, hard at work on its surface).