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Gewählte Master / Diploma Thesis:

Martin Weigl (2006): Annual and intra-annual variations of ring-widths and stable isotopes in sessile oak (Quercus petraea (Matt.) Liebl.)..
Master / Diploma Thesis, BOKU-Universität für Bodenkultur, pp 50. UB BOKU obvsg

Data Source: ZID Abstracts
A stem analysis was done with a sessile oak tree (Quercus petraea (Matt.) Liebl.) havested in the Lainzer Tiergarten, Vienna. The goal was to characterize the variability of ring-widths and stable isotopes (δ13C and δ18O) deposited in tree-rings, and demonstrate also the meaning of these analyses to reconstruct climate. Axial variation of latewood-widths and stable isotopes in latewood as well as the radial variation of widths and stable isotopes present in different tree-ring-sections of the tree, were investigated. To analyze the radial variations tree-rings were separated into early- and latewood, complete tree-ring and so-called transfer tree-ring, the latter being the latewood plus the earlywood of the subsequent year. The influence of sampling height was found to be weak for both latewood-widths and stable isotopes measured in latewood. The observed trends with stem-height show clearly that possible effects due to cambial aging are outperformed by the climatic influences. In addition, relationships between samples from different stem-heights are strong for identical calendar years, while they are poor for identical cambial age. All this indicates that samples from both, living trees and historical wood can be taken from any height position of a trunk or beam as long they are free from anatomical abnormities. Concerning radial variations, widths and δ18O-values showed low autocorrelation while most of the tree-ring parameters where highly autocorrelated for three out of the four δ13C parameters. Mean sensitivity of standardized values was in the range of 1.095 to 1.239 for widths and 0.712 to 0.954 for δ13C and 1.253 to 1.541 for δ18O. The statistical parameters Gleichläufigkeit, simple and partial correlations showed that relationships within the widths, δ13C and δ18O parameters are much stronger than across these parameter. This indicates the unique potential of each parameter for climate reconstruction. Correlation with temperature, precipitation and Oxygen isotopes in precipitation, i.e. GNIP-data, showed extraordinary high potentials of latewood-, tree-ring- and transfer tree-ring-widths and -δ18O for climate reconstruction. The best results along each of the three methods could be found for transfer tree-ring-width, latewood-δ13C and tree-ring-δ18O. For climatic studies, the selection of the best parameter (width, δ13C, δ18O) gives more significant results than a selection of different tree-ring sections (EW, LW, TR, TTR) using just one parameter.

Beurteilende(r): Wimmer Rupert

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