Impact of water level fluctuations on radial stem growth of Pinus sylvestris dominating on alluvial terraces

Impact of water level fluctuations on radial stem growth of Pinus sylvestris dominating on alluvial terraces

Annual rings of trees are most valuable and long-term climate proxy-data at an annual resolution. At the limits of tree growth like at the alpine treeline or within inner Alpine dry valleys, the year-to-year variability of ring widths reflects variation of climate conditions. Likewise, trees growing along riversides may store information on hydrological parameters like streamflow, water level fluctuations, and precipitation in their growth rings. Along the inner Alpine river Lech (Tyrol, Austria) Scots pine (Pinus sylvestris L.) dominates on alluvial terraces, which are made up of coarse calcareous gravel. These terraces are only occasionally subject to flooding and are dominated by poorly grown stands, which is supposed to be due to thin soils with low water holding capacity causing periodic drought stress to occur during the growing season. Recent dendroecological analyses, which are based on ring width series of P. sylvestris developed within this area (Polacek et al. 2006), revealed a close  inverse relationships between maximum water level during the growing period and annual increments of adult stands (r2>0.35). It is aimed at getting a more detailed interpretation of the relationship between growth, water level and climate by determination of onset, cessation and year-to-year variability of cambial activity concurrently with records of environmental parameters. Based on these results we will also focus on the development of a dendrohydrological model to reconstruct water level fluctuations for the last c. 250 years using well replicated ring width chronologies of P. sylvestris growing along the river Lech.

Publications
Polacek D., W. Kofler and W. Oberhuber (2006) Radial growth of Pinus sylvestris growing on alluvial terraces is sensitive to water-level fluctuations. New Phytologist 169:299-308.
 

Funding
Amt der Tiroler Landesregierung, Abteilung Umweltschutz (2003-2004)

Personnel involved
Klemens Handler
Daniel Polacek
Werner Kofler
Walter Oberhuber

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