the largest living organism, Armillaria ostoyae, also called honey mushroom , has been discovered spread over 890 hectares beneath the soil of the Malheur National Forest in eastern Oregon, usa.

The fungus started from a single tiny spore and has been spreading through the forest for an estimated 2,400 years, killing trees as it grows. According to a member of the research team, Greg Filip of the Forest Science Department, Oregon State University, the fungus is one of the major pathogens that cause death of conifers.

The presence of the fungus was indicated when there was a big tree die off due of root rot in the forest, east of Prairie City, Oregon. Researcher, Catherine Parks from Northwest Research Station identified the area showing dead trees from the air and took root samples from 112 trees. Using deoxyribonucleic acid tests, she found the fungus in 61 of them, showing that the fungus was growing all over the area.

According to Tina Dreisbach, botanist and mycologist with the us Forest Service, the dry climate in eastern Oregon may be one reason why the fungus has grown so huge. The fungus is found in all Northern Hemisphere, temperate forests and can attack both conifers and hardwoods.