For years the blue whale was considered that the largest living organism on the planet at more than 100 tons. But if sheer weight is the standard, the General Sherman sequoia in Sequoia National Park registers an amazing 4.5 million pounds. But two decades ago researchers announced they had found the largest living thing, at least in area, and claimed it weighed much more than a blue whale. It was a mushroom, of all things, and it covered 38 acres in northern Illinois. What we refer to as a mushroom is actually just the fruiting body; the real mushroom are the underground white mycelia threads, which pervade the soil. The media dubbed it the “humongous fungus."
Then some other scientists said "oh yeah? we got a bigger fungus”. This one in Washington State, which covered 1500 acres. And the ‘my fungus is bigger than your fungus’ contest escalated when another huge clonal group was discovered in Oregon, at 2000 acres.
But it turns out that fungi are lightweights in the size versus poundage debate over what constitutes the largest living organism. Scientists in Utah have been researching a huge colony of quaking Aspen trees in the Wasatch Mountains. This colony covers only 106 acres but sports 47,000 individual trunks, arising out of one single organism. Essentially every apparently separate aspen tree is connected underground by common room system. In other words, it is one huge genetically identical clone. They have named this "tree" Pando, which is Latin for “I spread.” And it weighs in at least 13 million pounds, dwarfing the General Sherman and outclassing the punchless fungi.
I was just up on the east side of the Sierra amid the changing autumn colors. If you observe a hillside full of aspen trees you too can easily see the clonal groups. With the same exact soil, exposure and rainfall, some aspens leaves are slightly different colors than other groups. This makes it very easy to distinguish the various clones. As for their weight? Well, that you’ll just have to guess.
This is Michael Ellis with a Perspective.