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Growing from tree trunks, these platter-shaped mushrooms connect to a network of tiny filaments that consume and rot the wood they grow in. They are important for decomposition and nutrient recycling in the forest.
The purpose of the shelf is to produce trillions of spores. Unlike most mushrooms, which can pop up overnight and rot away in days, these create a new under-layer of spore-producing tissue each year, like the growth rings of trees.
Red Ring Rot, Phellinus pini: A spore falls onto a small wound in a tree. Long thin networks of tissue slowly eat their way into the heartwood, rotting the tree from the inside out. Decades later, shelf fungi will grow at the base of a branch to spread their spores. Attacking living trees, this species is a parasite that can destroy timber value but also create homes for woodpeckers and other hollow-nesting creatures.
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Bear’s Bread, Fomitopsis pinicola: Find these woody knobs on snags and fallen logs throughout the forest. They always grow horizontally and will reorient themselves when their host snag topples. This species is a saprophyte—only eating wood that’s dead already. Extremely common, it plays a key role in breaking down dead wood and returning its nutrients to the soil.