Radiocarbon concentration in annual tree rings from the Salamanca region, Western Spain

Tree-ring samples were taken from a from a pine tree (Pinus pinea) growing in Villar de Peralonso, a rural area 50 km west of the city of Salamanca, Spain. All samples were processed to extract α-cellulose and the radiocarbon concentration in each annual ring was measured using accelerator mass spectrometry (AMS) at the University of Nagoya, Japan. The data set covers a growth period between 1979 and 2006, and represents the concentrations of ¹⁴C in a "clean area." The average difference between ¹⁴C concentrations in Villar de Peralonso and NH zone 1 for the period 1979-1999 is 4.1 ± 1.3‰. A sample was taken to obtain the reference level of ¹⁴C for the Iberian Peninsula, for a study of anthropogenic emission of CO₂ in urban areas. As part of the initial study, ¹⁴C concentration data in tree rings from the city of Valladolid were used to recalculate the fossil fuel component (cfoss) using reference data from Villar de Peralonso.