The distribution of Palmer's oak (Quercus palmeri Engelm.) includes numerous isolated populations that are presumably relicts of a formerly larger range that has contracted due to spreading aridity following the end of the Pleistocene.
In 2008 one red oak hybrid (Quercus rubra × ellipsoidalis) was diagnosed with oak wilt disease (Ceratocystis fagacearum) at Starhill Forest Arboretum in Illinois.
Many common native trees are just as beautiful as cultivated exotics. Since they have evolved with local conditions and are well adapted to their climate, they often require less maintenance and won't escape to invade a balanced ecosystem.