Tree-ring width measurements of Douglas fir from Otzweiler from 1925 to 2021@en

Wood samples from Douglas fir trees were taken using an increment borer. From each tree two opposing increment cores were taken at breast height. The sampled trees stood in an area of ~50x50 meters. Total ring width was measured and digitized. The resulting two radii measurements of each tree were visually synchronized and averaged to form a tree-ring series. Additionally, metadata were collected such as tree height, circumference and provenance (coastal, interior). The tree-ring data were used to investigate the resilience, resistance and recovery of the Douglas fir trees to severe drought events and to perform climate sensitivity analysis. This tree-ring dataset was part of a sampling campaign to assess the growth potential of Douglas fir trees until the year 2100. Annual tree growth variability until 2100 was modeled for Germany (including the river basins draining to Germany) with a spatial resolution of 12x12 km using regional climate projections ensemble.研究人员采用树木生长锥（increment borer）采集花旗松（Douglas fir）木材样本：每棵树在胸高位置采集两份相对方向的树木生长芯样。采样区域面积约为50×50米，区内分布所有待采样树木。对年轮总宽度开展测量并完成数字化处理后，对每棵树得到的两份半径测量值进行目视校准并取平均，以此构建单棵树的年轮序列。此外还采集了树木高度、胸径以及种源（沿海、内陆）等元数据。本年轮数据集被用于探究花旗松应对极端干旱事件的抗性、恢复力与灾后恢复能力，并开展气候敏感性分析。该数据集同时是一项采样研究计划的组成部分，该计划旨在评估花旗松至2100年的生长潜力。研究团队采用区域气候预估集合模式，以12×12公里的空间分辨率，对德国境内及所有汇入德国的流域范围内至2100年的树木年生长变异性进行了模拟。