Just a brief mention of an important palaeoclimatic paper (in Spanish language):
Pablo Ramil Rego, Cambio climático y dinámica del paisaje en Galicia (Climate change and environmental dynamics in Galicia). Recursos Rurais, 2009. (Direct PDF link).
Most informative is maybe figure 12, that I reproduce here:
It is pretty evident that in the Last Glacial Maximum (first map), the region was dominated by grass and mountain dwarf shrubs, but with importance of forest in the south (Northern Portugal) and even in Asturias (something I was not clearly aware of and that should be general for all the Cantabrian strip).
Forests gradually expanded in the Late Upper Paleolithic, as climate warmed gradually, becoming clearly dominant in the Epipaleolithic (last map), when climate was already pretty much like today's. Epipaleolithic would anyhow last for some three millennia after the period covered here.
Later deforestation is apparent (fig. 15) but mild at some locations since c. 5000 calBP (beginnings of Neolithic), in the Iron Age, but specially since the Roman and Medieval periods.
Found at Arquêociencias[por].