Quercus robur the oak tree at Boscobel House, where the future King Charles II hid from his Parliamentarian pursuers in 1650 during the English Civil War; the tree has since been known as the Royal Oak. This event was celebrated nationally on 29 May as Oak Apple Day, which is continued to this day in some communities. ‘The Royal Oak’ is the third most popular pub name in Britain (541 in 2007) and has been the name of eight major Royal Navy warships. The naval associations are strengthened by the fact that oak was the main construction material for sailing warships. The
Oak "Lymantria dispar", which can defoliate oak and other broadleaved tree species in North America. A considerable number of galls are found on oak leaves, buds, flowers, roots, etc. Examples are oak artichoke gall, oak marble gall, oak apple gall, knopper gall, and spangle gall. A number of species of fungus cause powdery mildew on oak species. In Europe the species "Erysiphe alphitoides" is the most common cause. A new and yet little understood disease of mature oaks, acute oak decline, has been reported in parts of the UK since 2009. Oak processionary moth ("Thaumetopoea processionea") has become a serious threat