Largest Organism Ever Found Discovered

truffler1635 at truffler1635 at
Sat Aug 5 09:59:31 EST 2000

The following is from The Oregonian, August 4, 2000, p B4

The fungus covers 2,200 acres and has been alive for 2,400 years

The Oregonian
	A fungus that is the largest living thing ever found has been
discovered in the Blue Mountains of Eastern Oregon near Prairie City.
	The fungus, Armillaria ostoyae, covers 2,200 acres in the Malheur
National Forest and is estimated to be 2,400 years old, said Catherine
Parks, a scientist with the U.S. Forest Service's Pacific Northwest
Research Station. Parks led the research, in cooperation with Oregon
State University.
	The fungus, technically a clone because it spreads from a single
individual, is nearly half again as large as the previous record holder,
an Armillaria ostoyae found in 1992 that covers 1,500 acres near the
southern foothills of Mount Adams in Washington.
	The massive organism, a root-rot fungus that causes wood decay,
stunts growth and sometimes kills trees, grows underground over an area
equivalent to nearly 3 1/2 square miles. Despite its size, few peole are
likely to have seen the fungus.
	"This fungus lives in a below-ground habitat," Parks said. The
outward signs of the fungal infection are the dead trees.
	"If you pull up the bark at the base of an infected tree, right
undeneath you will see a white mycelium felt, which peels back like latex
paint," Parks said. "It is all matted and thick."
	The fungus spreads underground through the upper soil, using black,
shoestringlike survival structures called rhizomorphs that grow as long
as 10 feet. When they contact a tree root, the rhizomorphs penetrate it
by a combination of mechanical pressure and enzyme action.
	Armillaria ostoyae produces clusters of golden-brown mushrooms, but
they are rarely seen in Eastern Oregon because of the climate.
	The lact of mushroom production helps explain why such a big fungus
is found there. The spores released by mushrooms are the product of
sexual reproduction and therefore grow into genetically different
individuals, rather than identical clones.
	Because so few mushrooms are produced, new, genetically different
Armillaria ostoyae individuals are rare. The original clone thus has the
habitat all to itself and can continue to expand via the rhizomorphs.
	How do scientists know that it's all the same organism, not many
similar organisms?
	"We did DNA fingerprinting and vegetative pairings," Parks said. In
vegetative pairings, scientists take samples from different sites and
grow them together on a petri plate. If the two samples grow together
seamlessly, they are considered to be the same organism. If they form a
barrier line on the petri plate, the researchers know they're genetically
	"It is all the same organism," Parks said. "It came from vegetative
growth and spreading of rhizomorphs. Also, it can grow on trees without
killing them. It has all kinds of pretty incredible strategies."
	Forest Service officials are not particularly worried about the
spread of the fungus, but they take it into consideration when planning
management strategies. When doing thinning, for example, the agency might
have the logging contractor target the susceptible species.
	Armillaria is the most common root disease in Oregon, but it can be
found around the world, said Greg Filip, an associate professor at OSU
who collaborated on the project. "There is a long history of research on
Armillaria because of its economic impact."
	The fungus degrades all the major wood components of a tree
simultaneously, progressively weakening it. "It's not a good thing if you
want to make 2xby-4s," Parks said.
	Because the fungus spreads slowly and doesn't affect every tree in
the same way, the economic impact is subtle. "It is hard to put numbers
on what it does, but it definitely contributes to lack of forest product
productivity," Filip said.
	But the fungus also plays an important natural role in the forest
ecosystem, Filip and Parks said. Armillaria helps wood decay and dead
trees create habitat for wildlife and contribute to nutrient recycling.

Comment from poster:
	No word yet on whether another site 30+ miles across near Crater
Lake of the same fungus is a single organism or not. Kind of difficult to
collect material on opposite sides of such an organism without GPS
assistance. <G>

Posted as a courtesy by
Daniel B. Wheeler

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