Occurrence of continuous Holocene pinewoods (Pinus sylvestris L.) in the Eastern Central System (Spain) inferred from macroremains. New data from the Sandria site

The present study of plant macroremains, wood fragments and pine cones from the eastern Central System (Ayllón Massif) for the upper Holocene establishes the presence in the area of Pinus sylvestris, Juniperus sp. and Betula sp. The occurrence of the Scots pine between ca. 4000 and 2000 yr BP allows us to confirm the natural origin of the species in the area at an altitude of 1350 m asl, a fact that clashes with numerous former phytosociological interpretations and which highlights the relevance of the current pine forests, as well as the need to include them within some status of legal protection. Furthermore, for the first time on the Iberian Peninsula, and considering the nearby Valdojos site, we employ only macroremains to demonstrate the presence of a pine forest practically throughout the Holocene, thus evidencing maximum conditions of stability and resilience for this type of plant community. As occurs with other vegetal formations identified by means of pollen analysis, this forest could have undergone radical alterations only in recent historical times as a result of anthropic action, as appears to be indicated by the evolution of the sedimentary basin of the Sandria valley.