It is sometimes treated as a subspecies of "Quercus petraea". The site is of importance due to its population of Sessile Oak ("Quercus petraea"). In the southern portion of the ecoregion "Quercus petraea" and "Q. pubescens" are also present. On more acid soils, sessile oak, "Quercus petraea", and birch, "Betula sp.", are dominant. The most common tree in the forest is sessile oak ("Quercus petraea"). Grasslees Wood is dominated by sessile oak ("Quercus petraea") with some birch ("Betula pubescens"). Derrycunihy Wood is perhaps the most natural sessile oak ("Quercus petraea") wood in Ireland. The larvae feed on "Quercus petraea", "Quercus pubescens" and "Quercus robur". Proanthocyanidins also may be isolated from "Quercus petraea" and "Q. robur" heartwood (wine barrel oaks). Procyanidins can also be isolated from "Quercus petraea" and "Q. robur" heartwood (wine barrel oaks). The larvae feed on "Quercus robur", "Quercus petraea" and "Quercus rubra". The larva feeds on "Quercus robur", "Quercus petraea", "Quercus cerris" and "Quercus ilex". The larvae feed on "Quercus cerris", "Quercus petraea", "Quercus pubescens" and "Quercus robur" species.