Maximum latewood density (MXD) chronologies have been widely used to reconstruct summer temperature variations. Precipitation signals inferred from MXD data are, however, rather scarce. In this study, we assess the potential of using MXD data derived from Scots pine (Pinus sylvestris L.) growing in the Stockholm archipelago (Sweden) to reconstruct past precipitation variability. In this area, slow-growing pine trees emerge on flat plateaus of bedrock outcrops with thin or absent soil layers and are, therefore, sensitive to moisture variability. A 268-year-long MXD chronology was produced, and climate–growth relationships show a significant and robust correlation with May–July precipitation (P_MJJr = 0.64, p < 0.01). The MXD based May–July precipitation reconstruction covers the period 1750–2018 CE and explains 41% of the variance (r²) of the observed precipitation (1985–2018). The reconstruction suggests that the region has experienced more pluvial phases than drought conditions since the 1750s. The latter half of the 18th century was the wettest and the first half of the 19th century the driest. Climate analysis of “light rings” (LR), latewood layers of extreme low-density cells, finds their occurrence often coincides with significantly dry (<41 mm precipitation) and warmer (1–2 °C above average temperature), May–July conditions. Our analysis suggests that these extremes may be triggered by the summer North Atlantic Oscillation (SNAO).

中文翻译：

---

利用来自斯德哥尔摩群岛的樟子松的MXD数据重建夏季降水

最大晚木密度（MXD）年代已被广泛用于重建夏季温度变化。但是，从MXD数据推断出的降水信号却很少。在这项研究中，我们评估了使用源自斯德哥尔摩群岛（瑞典）生长的苏格兰松树（Pinus sylvestris L.）的MXD数据重建过去降水变化的潜力。在该地区，生长缓慢的松树出现在基岩露头的平坦高原上，土壤层薄或没有土壤，因此对湿度变化敏感。产生了长达268年的MXD年表，气候与生长的关系显示与5月至7月的降水有显着且强有力的相关性（P _MJJ r = 0.64，p<0.01）。基于MXD的5-7月降水重建涵盖了1750-2018 CE时期，并解释了观测到的降水（1985-2018）的41％的方差（r ²）。重建表明，自1750年代以来，该地区经历了比干旱多的干旱时期。18世纪下半叶最潮湿，而19世纪上半叶最干旱。极低密度细胞的晚材层“轻环”（LR）的气候分析发现，它们的发生通常与五月至七月的明显干燥（降水<41毫米）和温暖（高于平均温度1-2°C）相吻合。条件。我们的分析表明，这些极端情况可能是由夏季北大西洋涛动（SNAO）触发的。