Hello Mushrooms on trees are a sign that the tree is suffering some type of damage. Mushrooms are the fruiting body of a fungus and usually appear after the fungus is established in the tree. This may mean that the tree is dying or has a disease that has compromised the interior of the tree. Fungi can attack roots directly or enter through a wound. Symptoms may appear as dying leaves and limbs, early fall color, discolored bark and lesions. However, once mushrooms are present, it is likely that the the fungus has progressed and serious damage has already occurred. It is unlikely that the tree can be saved. However, in order to have the tree properly evaluated, you should consult a certified arborist. You can find a certified arborist in your area at the International Society of Arboriculture’s website treesaregood.org,