The post-glacial history of Pinus sylvestris in the British Isles

A consideration of all available macrofossil and pollen data suggests that Pinus sylvestris entered England from the southeast just after 10,000 BP, and spread across nearly the whole of the British Isles, reaching northernmost Scotland by 4000 BP. Populations in western Ireland and northern Scotland may have had an independent glacial refugium (or refugia). Competition from deciduous trees such as Corylus avellana, Ulmus and Quercus, restricted the habitats available to P. sylvestris at about 9000 BP. At about 7500 BP, expanding populations of Alnus glutinosa replaced some of the remaining P. sylvestris populations. By about 4000 BP, P. sylvestris occurred only in northern and mountainous areas, on raised bogs, and on the limestone of the Burren, western Ireland. P. sylvestris over much of its range was severely reduced by the spread of blanket bog at about 4000 BP. This event may have been initiated by widespread climatic change.