I have seen Pleurotus on dead trees- oak and sycamore.
It is an annual fungus and is soft and fleshy. Oyster fungus is supposed to be very edible and has a strong smell. The colour can be quite variable. A good ident feature is that the gills run down to the stem.
Unlike Pleurotus ostreatus, the decay characteristics of Pleurotus dryinus are not documented in detail.