Radial growth variations of black pine along an elevation gradient in the Cazorla Mountains (South of Spain) and their relevance for historical and environmental studies

In southern Spain, the Cazorla Mountains (500-2,100 m a.s.l.) have supplied construction timber from black pine (Pinus nigra Arn.) for buildings and ships since at least the Middle Ages. To establish the age and provenance of wooden cultural heritage originating from this area, well-replicated long-span chronologies are needed. Old-living trees occur at high elevations, whereas many historical timbers originated from lower altitudes; hence, crossdating possibilities were questionable. To assess the potential of this species for the development of a multi-millennia tree-ring data set with living trees and historical timbers for the western Mediterranean, we developed four ring-width chronologies along the circa 1,000 m altitudinal range of black pine in these mountains and examined crossdating patterns and climate-growth responses along with altitude and through time. Teleconnections with other Iberian and Mediterranean tree-ring data were also tested. A well-replicated chronology spanning AD 1331-2009 was obtained at the upper site, while lower elevations delivered shorter chronologies. Similarity among chronologies and responses to climate were dependent on elevation. Tree-ring width was negatively related to temperature in previous late summer and positively to February-March, whereas precipitation had an opposite effect; some negative influence of early summer temperature was also observed. However, growth responses were rather unstable throughout the twentieth century. These chronologies showed good tele- and heteroconnections with conifer chronologies from Iberia, northern Morocco and Turkey, evidencing the existence of a common macroclimatic signal, which also varied along with elevation. The relevance of these results for dendrohistorical studies is discussed.