It is even difficult to imagine that a mushroom, or rather, a mycelium of the dark honey fungus, growing in the Malur Forest of Oregon (USA), has got into the list of the largest living organisms on Earth. The fungus lives on an area of almost 1,000 hectares, which is equal to approximately 1,600 football fields. It is 2,500 years old and weighs over 600 tons. The mushroom is also called the Oregon monster, or the mushroom monster. The reason for this name lies not in its colossal territorial scale and weight, but in the fact that the mycelium, entangling the roots of trees, causes their death. Already many trees in the reserve have become victims of this octopus, and it was from the mass death of plants that scientists learned about the giant.
Previously, the leader was considered the mycelium of the dark honeydew in Washington state on an area of 600 hectares. It is likely that larger myceliums also live on Earth, the existence of which is still unknown due to the difficulty of identifying them. “The phenomenon of a serial killer” of trees was explained as follows: a giant mycelium wraps around the roots of trees, introducing special thin threads - rhizoids - into the wood. Thanks to rhizoids, mosses, lichens, algae and fungi cling to the surface, in this particular case, to the bark and roots of trees, pumping out moisture and nutrients from them. Biologists, having carried out a comparative analysis with other fungi, found that the rhizoids of the dark honeydew have a unique genome that is able to perfectly and efficiently decompose lignin. And the main purpose of lignin, which is part of all terrestrial plants, is to ensure the tightness of the vessel walls,along which water and nutrients dissolved in it move.
The authors of the work suggested that, most likely, the ability to destroy the tissues of higher plants originated in the Oregon monster at a time when their ancestors ate only the wood of dead trees. In the course of evolution, they gradually adapted to the penetration of the bark of healthy plants, both conifers and a number of others. Their rhizoids, once penetrating under the bark, spread tens of meters, pumping out water saturated with nutrients along the way. Trees, entangled with rhizoids of the dark honeydew, die over time.
It is difficult to detect mycelium. Obvious evidence of its vital activity is organisms in the form of mushrooms with caps growing on tree stumps, trunks and roots. According to the authors of the study, today these largest organisms in the world pose a serious threat to forests, mainly conifers, causing seemingly unreasonable death of trees. There are almost no methods to effectively combat them. The researchers note that all types of honey agaric are devastating pathogens. Because of them, forests are often extinguished in many regions of the planet.