Tree growth ring data of Betula platyphylla var. japonica obtained in a 14-year-old stand at the experimental forest of the Hokkaido Research Center, FFPRI

Abstract The widths of tree growth rings of the main stems of 12 Betula platyphylla var. japonica individuals that were naturally regenerated in a birch stand at the Hokkaido Research Center were measured and converted to a machine readable data format. The sampled stems should have grown over 14 growing seasons. The individuals were felled in May 2019, and disks were sampled at 1-m intervals from a height of 0.3 m above the ground. The ring widths for every year were measured in four directions for each disk using a ring-measuring instrument. The number of cases where year-to-year change patterns in the ring widths were the same among the four examined directions was more than expected under the random condition. Finally, the data were assembled and saved as a comma-separated values file containing values for the mean radius of each stem, year, and height. In addition, stem analysis diagrams were drawn for each sampled stem. Data file structure Type: comma-separated values Character set: US-ASCII Newline code: LF Column description Tree: number of the sample tree Height: height of the disk (unit: m, accuracy: 0.1 m) Year: year of the ring formed Radius: mean of four radius lengths from the center to the outer edge of the ring (unit mm, accuracy 0.1mm)