title: Impacts of regional climatic fluctuations on radial growth of Siberian and Scots pine at Mukhrino mire (central-western Siberia).
abstract: Ring width (TRW) chronologies from Siberian (Pinus sibirica) and Scots (Pinus sylvestris) pine trees were sampled at Mukhrino - a large mire complex in central-western Siberia - to evaluate the impacts of hydroclimatic variability on tree growth over the last three centuries. For this purpose, we compared climate-growth correlation profiles from trees growing on peat soils with those growing on adjacent mineral soils. Tree growth at both peat and mineral soils was positively correlated to air temperature during the vegetation period. This finding can be explained by (i) the positive influence of temperature on plant physiological processes (i.e. growth control) during the growing season and (ii) the indirect impact of air temperatures on water table fluctuations. We observe also a strong link between TRW and the winter Palmer Drought Severity Index (PDSI), especially in Siberian pine, reflecting the isolating effect of snow and limited freezing damage in roots. Significant negative relations were, by contrast, observed between bog TRW chronologies and hydroclimatic indices during spring and summer; they are considered an expression of the negative impacts of high water levels and moist peat soils on root development. Some unusually old bog pines - exhibiting >500 growth rings - apparently colonized the site at the beginning of the Little Ice Age, and therefore seem to confirm that (i) peat conditions may have been drier in Siberia than in most other regions of western Europe during this period. At the same time, the bog trees also point to (ii) their strong dependence on surface conditions.
authors.affiliation: Laboratory of Ecological Systems, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Blanchet
authors.affiliation: dendrolab.ch, Institute of Geological Sciences, University of Bern, Baltzerstrasse 1-3, CH-3012 Bern, Switzerland.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Guillet
authors.affiliation: Laboratory of Ecological Systems, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Calliari
authors.affiliation: Geolab UMR6042 CNRS, Université Blaise Pascal, Clermont-Ferrand, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Corona
authors.affiliation: dendrolab.ch, Institute of Geological Sciences, University of Bern, Baltzerstrasse 1-3, CH-3012 Bern, Switzerland.
authors.forename: Johannes
authors.initials: J
authors.lastname: Edvardsson
authors.affiliation: dendrolab.ch, Institute of Geological Sciences, University of Bern, Baltzerstrasse 1-3, CH-3012 Bern, Switzerland; Climatic Change and Climate Impacts Group, Institute for Environmental Sciences, University of Geneva, 66 Bvd Carl-Vogt, CH-1205 Geneva, Switzerland; Department of Earth Sciences, University of Geneva, 13 rue des Maraîchers, CH-1205 Geneva, Switzerland. Electronic address: markus.stoffel@dendrolab.ch.
authors.forename: Markus
authors.initials: M
authors.lastname: Stoffel
authors.affiliation: Laboratory of Ecological Systems, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Swiss Federal Institute for Forest, Snow, and Landscape Research, WSL Lausanne, Station 2, 1015 Lausanne, Switzerland; Department of Life Science and Biotechnologies, University of Ferrara, Corso Ercole I d'Este 32, Ferrara 44121, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Bragazza
keywords: 3-month SPEI; Dendroclimatology; PDSI; Peatland