Fall is when mushrooms and shelf-like fungi start popping up around Treasure Valley yards. Most of the ones in the lawn are harmless, but mushrooms or hard, shelf-shaped conks growing on a tree's trunk, root flare, or major roots are a different story.
These are the visible fruiting bodies of wood-decay fungi, and by the time they appear, the fungus has usually been working inside the wood for years. Depending on the species, the decay may be in the roots that anchor the tree or in the lower trunk, where strength matters most. A tree can still have a full, green canopy while the structure underneath is weakening.
A conk doesn't automatically mean a tree has to come down. Our ISA Certified Arborists identify the fungus, check how much sound wood remains, and give you an honest recommendation, which sometimes means monitoring instead of removal.
Have you spotted mushrooms or shelf fungi growing on any of your trees this fall? #TreeHealth
Close-up photo of a shelf fungus or conk at the base of a tree trunk from a real ArborSafe assessment, ideally with an arborist inspecting it. Authentic ArborSafe job photos strongly preferred over stock.
Canva text suggestion: "Fungus on the Trunk Means Look Closer" or "Conks Can Signal Hidden Decay"