Consider the appearance of mushrooms on the trunk or root flares an urgent problem. While some mushrooms are harmless, others are usually a sign that there is decay in your tree’s roots or trunk — or both. And when there is decay, there is often risk that the tree will break or fall over. Depending on the size of the tree, this could spell T-R-O-U-B-L-E for whoever or whatever is underneath it.
The mushrooms illustrated below are considered deadly to a tree.
If you see any of these types of mushrooms (or others) at the base, on the trunk, or on the ground around your tree, DON'T REMOVE THEM! Call a Certified Arborist immediately. The arborist you call should have a Resistograph, an invaluable tool when a tree has decay. This machine will tell you how much decay there is and how deep it goes into the tree or its roots. This information is critical to making a decision about whether or not the tree should be removed.