What fungi is this?
MUSHROOMS AND OTHER FRUITING BODIES of fungi are commonly found after adequate rains in spring and summer. Fungi produce threadlike vegetative bodies (hyphae or mycelia) that grow through the soil and feed on organic matter. They produce enzymes that can degrade vegetation, insect bodies, and wood, and then they absorb the simpler sugars. Fungal hyphae grow under the ground in spring and summer and then produce their spore bearing structures in the fall. Some fungi have spores that are air-borne, whereas some rely on animals and insects to spread spores, and some are under ground, like truffles. Many mushroom producing fungi are mycorrhizal with plants, in a growth relationship that is mutually beneficial to both organisms. Sometimes if you know the type of tree you can predict the mushrooms that may grow nearby.
I believe the picture you sent is of Ganoderma aplanatum, the reishi conk. Heart rot and wood rot fungi may produce bracket or conks of the sides of trees or near the base. Once these brackets or conks are seen, it usually means that the tree is heavily colonized and compromised within. An example is Ganoderma, a fungus that causes heart rot or butt rot of trees. Once you see the typical reddish brown brackets with a light colored underside, the tree is rotted in the center. Trees can wall off infection or remain in relatively good health despite fungal infections, but will decline over time and more rapidly with environmental stress effects.
This fungal fruiting body would not be toxic or poisonous to animals.
Thank you for contacting Cooperative Extension,