New pollen-analytical data from the Navarrés peatbog (Valencia, eastern Spain) show a synchronous Late-Quaternary fluctuation of P. pinaster- (cluster pine) and Quercus- (oak) dominated assemblages. During glacial times, P. pinaster survived in refugia together with other trees such as Corylus, Fraxinuv Quercus, and a number of Mediterranean shrubs such as Arbutus, Erica arboreal Olea, Phyllirea, Pistacia terebinthus, Myrtus communis and Viburnum finus. These nuclei of vegetation expanded around c. 30 000-27 000 BP invading areas formerly occupied by pine forests. P. pinaster retreated considerably during the last glacial maximum and the Younger Dryas event, but not as much as Quercus. During c. 10 00-6000 BP, a local pine forest resisted possible oak and P. pinaster invasion. Around 6000 BP, P. pinaster was involved in a post-fire change towards oak-dominated vegetation. This work supports the contention that P. pinaster is native to the Iberian Peninsula and that well-developed P. pinaster forests, particularly if mixed with oaks, are a natural feature of the landscape. The data presented here disagree with the floristic-phytosociological assumption that considers that the forest patches of P. pinaster and other Mediterranean species of pines are incidental and mainly derived from afforestation.