Two modern tree-ring width chronologies of Pinus sylvestris L. have been established in an area near the southern limit of the species distribution. Trees were sampled in the south of Catalonia in northeastern Spain where mediterranean climatic conditions are of primary influence. To better understand climate ring-width relationships, tree-ring index series have been studied in relation to local climate. Ring-widths are strongly related to low precipitation at the beginning of the growing season in March, in June of the current growth year, and in September prior to tree-ring growth. [...].