Both Sessile Oak Quercus petraea and Pendunculate Oak Quercus robur, Britain's two native oaks are used and also some introduced species such as Turkey Oak Quercus cerris and Evergreen oak Quercus ilex.
Quercus robur | Quercus ilex | Quercus petraea | Quercus alba | Quercus cerris | Quercus virginiana | Quercus rubra | Quercus garryana | Quercus acutissima | Quercus palustris | Quercus minima | Quercus fusiformis | Quercus castaneifolia | Quercus agrifolia | sand live oak (''Quercus geminata'') | Quercus × warei | ''Quercus'' × ''warei'' | Quercus suber | ''Quercus robur'' | Quercus peninsularis | Quercus lusitanica | Quercus lobata | Quercus laceyi | Quercus ilicifolia | Quercus hemisphaerica | Quercus havardii | Quercus glauca | Quercus frainetto | Quercus engelmannii | Quercus copeyensis |
Several species of deciduous oaks (most prominently Quercus frainetto Ten., as well as Q. cerris L., Q. pubescens Willd. and others) dominate most of the ecoregion's forests, interspersed higher up mountainsides (above 800–1200 m) mostly with European Beech and such conifers as Scots Pine, Macedonian Pine, Silver Fir and Norway Spruce.
He later observed that these features occurred where both parents (Turkey Oak and Cork Oak) grew.