Driftwood supply was a pivotal factor for the Norse expansion in medieval times and still exhibits an essential resource for Arctic settlements. The physical causes and societal consequences of long-term changes in the distribution of Arctic driftwood are, however, poorly understood. Here, we use dendrochronology to reconstruct the age and origin of 289 driftwood samples that were collected at remote shorelines in northeast Iceland. Based on 240 reference tree-ring width chronologies from the boreal forest zone, and an overall provenance success of 73%, we show that most of the driftwood is pine and larch from the Yenisei catchment in central Siberia. Our study reveals an abrupt decline in the amount of driftwood reaching Iceland since the 1980s, which is corroborated by the experience of local farmers and fishers. Despite the direct and indirect effects of changes in both, logging activity across Siberia as well as Arctic Ocean currents, the predicted amount of sea-ice loss under anthropogenic global warming is likely to terminate Iceland's driftwood supply by 2060 CE.

浮木供应是中世纪北欧扩张的关键因素，仍然是北极定居点的重要资源。然而，人们对北极浮木分布长期变化的物理原因和社会后果知之甚少。在这里，我们使用树木年代学来重建在冰岛东北部偏远海岸线收集的 289 个浮木样本的年龄和来源。基于来自北方森林区的 240 个参考树轮宽度年表，以及 73% 的总体来源成功率，我们表明大部分浮木是来自西伯利亚中部叶尼塞集水区的松树和落叶松。我们的研究表明，自 1980 年代以来，到达冰岛的浮木数量急剧下降，当地农民和渔民的经验证实了这一点。