By Judy Kunz, Colorado Master Gardener
Nature’s Natural Recycler
If you’ve ever been hiking in the back country and have seen growing or fallen trees or tree stumps with woody, ruffle-type growths on them, you have probably seen bracket or shelf fungi. This unusual appearing phenomenon is a reflection of the decomposition process. The shelves are actually the organisms’ fruiting bodies, spreading fungi through airborne or soil borne microscopic spores. As they blanket their food source, they absorb minerals and sugars to aid in their growth, usually adding a new layer every year. Bracket fungi are an important part of a forest ecosystem, digesting and recycling living or dead organic matter and providing a habitat for insects and small animals. However, in an urban setting, bracket fungi can be a signal that the structural integrity of a tree has possibly been compromised by decay. In this situation it is best to consult a certified arborist.
For further information, see this link from Michigan State University.