A forest that is one tree

The ready availability of genetic testing has allowed biologists to find out how big single organisms can get. We have already learned about giant fungi that stretch across acres of forest and weight upwards of 500 tons. And now comes word of something even bigger:

The largest organism on Earth, and probably the oldest multicellular organism, is named Pando. Kind of a cutesy name for such an impressive specimen, don’t you think?

If you were to meet Pando — which you could easily do, if you paid a visit to Fishlake National Forest in Utah — it would look like a forest of Quaking Aspen trees. But if you happened to be equipped to do DNA testing on plant specimens, you would realize that all of the trees were genetically identical. That’s because they’re all part of the same tree, sharing a common root system. One tree springs from a seed, long ago, and spreads out roots; but then more trees erupt from those roots, and the process simply continues. Individual “trees” might die, but that’s like you or me losing a toenail; Pando lives on. It weighs in at over six million kilograms, and is likely more than 80,000 years old (although it might be much older).

Pando was discovered and named in the 1970s, but until recently the genetic identity of the whole organism or colony or whatever you want to call it was only a hypothesis. According to wikipedia, it has about 47,000 trunks. Since the organism as a whole can easily survive the death of one trunk or a thousand, and since it seems already to have survived severe fires that destroyed everything above ground, it could live pretty much forever.