This is a bracket fungus called Turkey Tail fungus (Trametes versicolour).

It prefers beeches and oaks and usually grows in semi circles with the rings on it can be found in many different colours! This type of fungus grows all year round but you notice this more in the winter when there are no leaves around to hide it!

Underneath it has tiny tubular shaped pores unlike mushrooms with their straight line gills.

This photo was taken here at Milntown so head down and see if you can spot any.