one flicker user has created what he calls the memory branch.
this guy actually shoved the silica guts of a functional thumb drive into a piece of wood, in essence manifesting a pun that most people have thought and kept to themselves. here’s what he has to say about it:
A USB stick in a section of a branch I picked up off the forest floor. I’ve seen this idea around once or twice and wanted to make my own, so I did! The difference is that mine still has bits of lichen attached to it.
you can read more about this and the comments that go with it on his flikr account.