Tree-ring d13C records from living trees and Oligocene wood fossils from Nanning China, with seasonal paleoclimate proxy results

Two radial cores (QXS21A and QXS24A) from living Pinus massoniana trees growing at Qingxiushan Hill, Nanning, Guangxi, China (22°47'23.35” N, 108°23'4.26” E, elevation = 223 m) were collected in 2016 using an increment borer. Consecutive growth rings spanning the years 1990 to 2000 were selected from each core for analysis. Each ring was subdivided by hand using a razor blade parallel to the direction of growth. A total of 317 subsamples were collected from across the two cores.