Tree at the ends of the world.

I was thinking about the tree of life. It seems to be the only feature other than God that is persistant throughout all of creation, right from the begining to the end. Even more interesting is that the tree of life is large enough to be growing on both sides of the river of life. A river flowed through eden, did the tree of life span it as well? Is it the same river? Although all life was destroyed in the flood, many plants survived (Noah didn’t take plants on board the Ark) which makes you wonder…is it the SAME tree of life as well?