Tree-ring width measurements of Douglas fir from Thurnau from 1902 to 2021

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.

研究人员采用增量钻（increment borer）采集花旗松（Douglas fir）的木材样本：每棵树于胸高位置采集两份相对朝向的钻芯样本。采样树木均分布于约50×50米的区域内。研究人员对树木年轮总宽度开展测量与数字化处理。针对每棵树获取的两份径向年轮宽度测量值，经目视对齐后取平均，以此构建单棵树的年轮序列。此外还采集了树高、胸径以及种源（沿海、内陆）等元数据（metadata）。研究团队利用该年轮数据集，探究花旗松对极端干旱事件的抵抗力、恢复力与恢复速率，并开展气候敏感性分析。该年轮数据集是一项采样调查计划的组成部分，该计划旨在评估花旗松至2100年的生长潜力。研究以12×12千米的空间分辨率，借助区域气候集合预测（regional climate projections ensemble）模式，对德国（含所有汇入德国的流域）直至2100年的树木年生长变异性进行了模拟。