<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Greater warmth and precipitation over the past several decades in the High Arctic, as recorded in meteorological data, have caused shrub expansion and affected growth ring widths. The main aim of the study was to develop a tree-ring chronology of polar willow (<italic>Salix polaris</italic> Wahlenb.) from southwest Spitsbergen, attempt to explain its extreme pointer years (extremely low value of growth-ring widths) and to demonstrate the dendrochronological potential of this species. This plant is a deciduous, prostrate, creeping dwarf shrub that produces anatomically distinct annual growth rings with the consistent ring width variation. After using serial sectioning we developed rigorously cross-dated ring width chronology covering the period 1951–2011. Since the beginning of the 1980s an increase of the mean and maximum growth ring width has been observed which is consistent with the increase of both temperature and precipitation in the Arctic reported from meteorological sources. Nine negative extreme years were distinguished and explained by complex hydroclimatic drivers, which highlight the importance of availability of moisture from snowpack and spring precipitation. An additional negative factor present in the years with very low dwarf shrubs growth is rapid thawing and fast freezing during winter as well as low sunshine duration. Our results contradict the prior assumption that inter-annual tree growth variability of dwarf shrubs from polar regions is controlled simply by temperature.</p></abstract>

Greater warmth and precipitation over the past several decades in the High Arctic, as recorded in meteorological data, have caused shrub expansion and affected growth ring widths. The main aim of the study was to develop a tree-ring chronology of polar willow (Salix polaris Wahlenb.) from southwest Spitsbergen, attempt to explain its extreme pointer years (extremely low value of growth-ring widths) and to demonstrate the dendrochronological potential of this species. This plant is a deciduous, prostrate, creeping dwarf shrub that produces anatomically distinct annual growth rings with the consistent ring width variation. After using serial sectioning we developed rigorously cross-dated ring width chronology covering the period 1951–2011. Since the beginning of the 1980s an increase of the mean and maximum growth ring width has been observed which is consistent with the increase of both temperature and precipitation in the Arctic reported from meteorological sources. Nine negative extreme years were distinguished and explained by complex hydroclimatic drivers, which highlight the importance of availability of moisture from snowpack and spring precipitation. An additional negative factor present in the years with very low dwarf shrubs growth is rapid thawing and fast freezing during winter as well as low sunshine duration. Our results contradict the prior assumption that inter-annual tree growth variability of dwarf shrubs from polar regions is controlled simply by temperature.

Dendrochronology and extreme pointer years in the tree-ring record (AD 1951–2011) of polar willow from southwestern Spitsbergen (Svalbard, Norway)

University of Wroclaw, Institute of Geography and Regional Development, Pl. Uniwersytecki 1, 50-137 Wroclaw,

University of Silesia, Faculty of Earth Sciences, Centre for Polar Studies KNOW (Leading National Research Centre), Bedzinska 60, 41-200 Sosnowiec,

University of Silesia, Faculty of Earth Sciences, Department of Climatology, Bedzinska 60, 41-200 Sosnowiec,

Geochronometria

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Greater warmth and precipitation over the past several decades in the High Arctic, as recorded in meteorological data, have caused shrub expansion and affected...

Dendrochronology and extreme pointer years in the tree-ring record (AD 1951–2011) of polar willow from southwestern Spitsbergen (Svalbard, Norway)

Article Category: Research Article

Pubblicato online: 13 giu 2016

Pagine: 84 - 95

Ricevuto: 01 ott 2015

Accettato: 21 apr 2016

DOI: https://doi.org/10.1515/geochr-2015-0035

Parole chiave
High Arctic, dendrochronology, climate, extreme pointer years,

© 2016 P. Owczarek and M. Opała

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Dendrochronology and extreme pointer years in the tree-ring record (AD 1951–2011) of polar willow from southwestern Spitsbergen (Svalbard, Norway)

Article Category: Research Article

Pubblicato online: 13 giu 2016

Pagine: 84 - 95

Ricevuto: 01 ott 2015

Accettato: 21 apr 2016

DOI: https://doi.org/10.1515/geochr-2015-0035

Parole chiaveHigh Arctic, dendrochronology, climate, extreme pointer years,

© 2016 P. Owczarek and M. Opała

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Parole chiave
High Arctic, dendrochronology, climate, extreme pointer years,