'Immortal' Trees Can't Escape Aging

"With immortality comes immobility.

Because some quaking aspen trees can reproduce by copying themselves, some people have wondered whether they might live forever, at least theoretically. But even if that's possible, they're still not immune from the ravages of time.

As aspen clones grow older, a slow buildup of genetic mutations impairs their pollen production. After a few tens of thousands of years, they won't produce any pollen at all.

When that happens, trees will still be able to sprout...