It is a parasite on the wounds of deciduous trees, especially sugar maple, beech and ash. It can also fruit on standing dead trees. From a distance, Climacodon septentrionalis looks like it is a polypore growing in tiered layers, but its spore-brearing surfaces are actually ‘toothed’ having spines rather than pores. This fungus causes rot of the tree's heartwood.
Younger specimen compared with the one in the top photo. Climacodon septentrionalis