A dead tree on our farm has a fascinating display of Shelf Fungi, and a fallen tree has a different variety.
“Fungi are important organisms that serve many vital functions in forest ecosystems including decomposition, nutrient cycling, symbiotic relationships with trees and other plants, biological control of other fungi, and as the causal agents of diseases in plants and animals.” (USDA)
Shelf fungi make shelves or brackets that stick out from the tree to produce spores above the ground. They are known as polypores (many pores) because, instead of having spore producing gills, they have many pores lined with spore producing cells called basidia. Like all fungi, bracket fungus likes a damp environment.
Shelf fungi, also called bracket fungus(i), can be woody, leathery or fleshy. Woody shelves can be several years old. They add a new layer of spore tissue every growing season, as the old layer is covered by the new one. Woody shelves are impossible to break with your hands and difficult to cut. This toughness results from the kinds of hyphae (filaments) that are used to construct the shelf.
Tree bracket fungus is a disease of the tree’s heartwood. The shelves are the fruiting bodies and by the time they appear, there is usually a significant amount of interior damage. The fungi that cause bracket fungus attack the hardwood interior, and therefore, the structural integrity of the tree and are the cause of white or brown rot. The mycelium, body of the fungus, decomposes chemicals in the tree cells. Unfortunately, there is no treatment for the removal of bracket fungus.
Read more about Polypores at these and other sources.
“Shelf Fungi.” Intermountain Herbarium, Dept. of Biology. College of Science, Utah State University. https://herbarium.usu.edu/fun-with-fungi/shelf-fungi
Rhoades, Jackie. “Tree Bracket Fungus – Learn About Prevention and Removal of Bracket Fungus.” Gardening Know How. https://www.gardeningknowhow.com/ornamental/fungus-lichen/tree-bracket-fungus.htm
Ostry, Michael, Neil A. Anderson, and Joseph G. O’Brien. Field Guide to Common Macrofungi in Eastern Forests and Their Ecosystem Functions. USDA. Forest Service. General Technical Report NRS-79.
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