Ring-widths from "Hydroclimate-driven societal change in Iran inferred from a 517-year precipitation reconstruction"

In spring 2018, 96 healthy Juniperus polycarpos trees were sampled using a 5.5 mm diameter, 400 mm long increment borer (Haglöf, Sweden). Tree ring widths were measured from bark to pith, to an accuracy of 0.01 mm. Cores from each tree were cross-dated using TSAPWin software (version 4.81) to ensure sample quality and validate their suitability for dendrochronological analysis. Two cores/tree were averaged to develop the ring-width chronology. In adopting this approach, we were aware that the resulting chronology incorporates both within-tree and between-tree signals. The study area is located in the northern highlands of Kerman province, situated in the southeastern part of the Central Iranian Plateau, between the cities of Ravar, Zarand, and Kuhbanan. This mountainous region extends 40 kilometers east-west and 60 kilometers northwest-southeast, with its highest peak (Kuh-e Gav) reaching an elevation of 3515 meters above sea level (31°25'N, 56°50' E). The Persian juniper (Juniperus polycarpos K.Koch) is distributed in the northern and northeastern parts of these highlands, primarily on steep slopes and rocky areas near the ridgeline. Juniperus polycarpos is most abundant on the southern, southwestern, and western slopes of the study area, while their numbers and density are lower on the eastern and northern slopes.