The main objectives of the thesis submitted were to create the missing oak tree-ring chronology for the area of Slovakia, update the existing Czech oak tree-ring chronology, assess their paleoclimatic potential, and find the best way to remove the age trend from tree-ring series. At the same time, the number of sapwood tree rings over time was analysed. As the historical and archaeological material can be represented in tree-ring chronologies by curves from different oak species with different age and from different areas, two comparative studies have been carried out to assess their usefulness for the climate reconstruction. Tree-ring chronologies of four selected oak species (Quercus robur L., Quercus petraea (Matt.) Liebl., Quercus polycarpa Schur., Quercus dalechampii Ten.) from the same region showed a very similar response to climatic parameters; the differences were caused by local site conditions rather than oak species. Further, the recent part of the Czech oak chronology was divided into five couples of sub-chronologies using various categories (altitude, age of trees, tree species, soil moisture, and geographic location). A great similarity of all the sub-chronologies was confirmed by the most significant growth response of oak to the precipitation sum in the period May to July. The thousands-year-long Czech oak chronology, which has been gradually improved in recent years, still showed insufficient coverage of the entire territory of the oak natural distribution range and insufficient replication in the 19th century. A total of 342 newly collected samples from western Bohemia and samples from selected historical structures, mostly belfries, were used to cover the entire natural distribution range in the Czech Republic and to improve the connection of the recent and the historical parts of the chronology. The study was supplemented by the analysis of the number of sapwood tree rings, which confirmed the declining number of sapwood rings in the direction from the west to the east, and showed that the number of sapwood rings does not change over time (5-24). A completely new tree-ring oak chronology for the territory of the Slovak Republic was made up of 276 historical and 1028 recent samples. The chronology ranges from 967 to 2013 and shows strong resemblance with the tree-ring chronologies from the Czech Republic, Austria and Ukraine. As the Czech chronology, it manifests the most significant response to precipitation in the May to July period with a huge drop in correlations around 1980. The analysis of negative pointer years in the chronology revealed 26 periods; the most extreme year was 1947, which stood out in all of the investigated sites. Comparing the resulting chronologies, no significant differences were found among the various ways of age trend removal from tree-ring series in the periods with sufficient replication. This work extends the knowledge about the behaviour of the oak in Central Europe at the level of tree rings. The newly formed tree-ring oak chronology for the area of Slovakia fills the gap in the dense network of European chronologies and together with the update of the Czech oak chronology increases the potential for hydroclimatic reconstructions and the reliability of the dating of historical oak structures and archaeological finds.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:425354 |
| Date | January 2016 |
| Creators | Prokop, Ondřej |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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