The U.S. Forest Service has adopted an informal live-and-let-live policy for the enormous tree killer it calls the "humongous fungus."

The huge root-rot infestation underlies 2,200 acres east of Prairie City in a remote corner of eastern Oregon’s Blue Mountains at an elevation of about 6,500 feet near the Strawberry Mountain and Monument Rock wilderness areas.

The Forest Service plans to publish a brochure about the gigantic fungus, Armillaria ostoyae, this summer. "There is no way to eliminate it," said Malheur National Forest ecologist and tree expert Mike Tatum of John Day.

Most people walking by would never know the fungus lurks just below the ground’s surface, occupying its time in the quiet business of sending out shoestring-like tentacles called rhizomorphs and wrapping them around tree roots.

Its sheer mass — it’s roughly the size of 1,600 football fields — makes Herman Melville’s fictional white whale Moby Dick seem like a tadpole. And it could get bigger.

In terms of age, Armillaria is a fungiform Methuselah. Researchers say it may have been 100 years old when Alexander the Great conquered the known world in 330 B.C. And some estimates suggest it could be 8,000 years old, said Forest Service researcher Catherine Parks, who has spent 10 years studying it.

Through DNA fingerprinting and a process called vegetative pairing, Parks’ research team determined that Armillaria is a single organism and therefore the biggest living thing on Earth.

Source: The Oregonian via Spluch