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Winter‐drought induced embolism in Norway spruce ( Picea abies ) at the Alpine timberline
Author(s) -
Mayr Stefan,
Wolfschwenger Marion,
Bauer Helmut
Publication year - 2002
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.2002.1150108.x
Subject(s) - picea abies , xylem , hydraulic conductivity , karst , tracheid , frost (temperature) , drought stress , abies lasiocarpa , environmental science , biology , botany , geology , ecology , pinus contorta , geomorphology , soil water , paleontology
At the timberline in the Central Alps, climatic conditions during winter frequently cause excessive drought stress (frost drought, ‘Frosttrocknis’), which we hypothesized to induce cavitation in trees. We investigated the extent of winter‐embolism in Norway spruce ( Picea abies (L.) Karst.) growing near the timberline and analysed adaptations in vulnerability and anatomy. We found conductivity losses of up to 100% at the highest elevation (2020 m) correlated with low water potentials down to − 4.0 MPa. Vulnerability thresholds (50% loss in conductivity) decreased from − 3.39 MPa at 800 m to − 3.88 MPa at 1600 m corresponding to a decrease in tracheid cross‐sectional area as well as pit and pit pore diameters. These thresholds were lower than potentials measured in embolized twigs near the timberline at the sampling dates probably due to lower potentials and/or a role of freeze‐thaw events earlier in winter. Data indicated refilling processes, which may be of particular relevance for trees at the timberline, since adaptations in drought‐induced vulnerability failed to prevent winter‐embolism.