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The Arctic is one of the regions most sensitive to global warming, for which climate and environmental proxy archives are largely insufficient. Arctic driftwood provides a unique resource for research into the circumpolar entanglements of terrestrial, coastal and marine factors and processes – past, present, future. Here, first dendrochronological and wood anatomical insights into 639 Arctic driftwood samples are presented. Samples were collected across northern Norway (n =430) and north-western Iceland (n =209) in 2022. The overall potentials and limitations of Arctic driftwood to improve tree-ring chronologies from the boreal forest, and to reconstruct changes in sea ice extent and ocean current dynamics are discussed. Finally, the role driftwood has possibly played for Arctic settlements in the past hundreds of years is examined. [ABSTRACT FROM AUTHOR]

Climatic parameters are the main environmental factors affecting tree growth. The main aim of the presented study was to determine whether different oak species growing under contrasting environmental conditions show different sensitivity to climatic parameters. Four oak stands with Quercus robur, Quercus petraea, Quercus polycarpa and Quercus dalechampii growing in the same area were evaluated. Standard dendrochronological methods were used for sample preparation, ring width measurements, cross-dating, chronology development, and the assessment of growth-climate response patterns. Although the species grew under different environmental conditions, their local tree-ring chronologies are highly correlated. The radial growth responses to climatic parameters differ slightly, but the response depends more on local site conditions than on the oak species. At the same time, the strongest correlations between radial growth and climatic parameters were identical among species and sites. The amount of water available in the soil was the main climate-dependent factor limiting radial growth. Approximately since the 1990s, the distribution of rainfalls within the growing season has changed at the expense of spring precipitation. The significance of relative soil moisture content during spring for oak growth increased and the significance of summer values decreased. [ABSTRACT FROM AUTHOR]

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. • Driftwood was and is the most important resource for all Arctic settlements. • Most of the Icelandic driftwood originates from the Yenisei catchment in central Siberia. • An abrupt decline in the amount of Icelandic driftwood supply occurred in the 1980s. • Icelandic driftwood supply will cease under predicted sea-ice loss by 2060 CE. [ABSTRACT FROM AUTHOR]