|
|
Quantitative vessel parameters of broadleaves as a tool for reconstruction of physical geographical processes
Tumajer, Jan
Trees adjust wood anatomical structure to environmental conditions, predisposing time series of quantitative wood anatomical parameters to be valuable source of palaeoenvironmental information. In this doctoral project we analysed the response of vessel parameters of i) floodplain Quercus robur to groundwater level fluctuation, hydroclimate variability and extreme events (droughts and floods), and of ii) Betula pendula to mechanical damage caused by various disturbances. Although climatic signal as well as pointer years stored in tree-ring width chronologies of Quercus robur largely differ between sites, quantitative vessel parameters contain spatially- homogenous positive signal of previous year summer temperature and current year winter/early spring temperature. The only between-site difference in wood anatomical chronologies is negative effect of moisture on vessel size in floodplain, which does not occur in not-flooded lowland sites. We suggest that while tree productivity benefits from high water availability, the wood anatomical structure of Quercus robur is constrained by high soil water saturation in floodplain zone. In addition, the response of tree-ring widths to moisture availability is not uniform inside single stand, but subgroups of trees with completely opposite response coexist...
|
|
|
The morphology and activity of selected avalanche paths in the Hrubý Jeseník Mts. and the Králický Sněžník Mts.
Krause, David
The occurrence of avalanche paths is usually frequent in alpine environment, but it is also present in mid-mountains such as the High Sudetes. The submitted master thesis is focused on avalanche paths in the Eastern High Sudetes. The morphometric analysis of 8 paths was accomplished to determine their characteristics and comparison with statistical verification. The dendrogeomorphological analysis and further geomorphological mapping was performed in 2 selected paths (Sněžná kotlina and Králický Sněžník) to cover their avalanche activity frequency and to find relationship between their activity and morphology. The results of this study show that there is a strong difference between two groups of avalanche paths in the Eastern High Sudetes. The Sněžná kotlina and The Králický Sněžník avalanche paths are longer and narrower than the other paths. They also have higher elevation difference. The comparison of these two paths performed by dendrogeomorphology indicates higher avalanche activity frequency in the Sněžná kotlina path, which was strengthened after strong avalanche event in 2004. It is assumed that the Sněžná kotlina path contains advanced avalanche landform, which is a long gully, probably also affected by debris- flows in the past. On the other hand the Králický Sněžník path is rather less...
|
|
|
Presentations for tourists of old timber roofs in historic towns
Bláha, Jiří ; Panáček, M.
The present state of knowledge and documentation of historical roof trusses in Czech towns. An overview of the educational and leisure orientated activities of the last decades. Creating the concept of enhancing the historical towns as tourist attractions with the addition of tours accessing historical timber roofs and other significant artefacts of structural history situated in related attic spaces. It is a by-product of long-term research activities focused on building heritage identification and preservation, manifestations of regional cultural diversity and the transfer of historical technological innovations in Europe. Improvement of awareness for both professionals and the general public of traditional building carpentry, construction development and their manifestation in the urban environment. The first experiences of the realization of the tour route “Under the Roofs of the Cheb Houses” which was established in 2017.
|
|
|
Quantitative vessel parameters of broadleaves as a tool for reconstruction of physical geographical processes
Tumajer, Jan ; Treml, Václav (advisor) ; Kolář, Tomáš (referee) ; van der Maaten, Ernst (referee)
Trees adjust wood anatomical structure to environmental conditions, predisposing time series of quantitative wood anatomical parameters to be valuable source of palaeoenvironmental information. In this doctoral project we analysed the response of vessel parameters of i) floodplain Quercus robur to groundwater level fluctuation, hydroclimate variability and extreme events (droughts and floods), and of ii) Betula pendula to mechanical damage caused by various disturbances. Although climatic signal as well as pointer years stored in tree-ring width chronologies of Quercus robur largely differ between sites, quantitative vessel parameters contain spatially- homogenous positive signal of previous year summer temperature and current year winter/early spring temperature. The only between-site difference in wood anatomical chronologies is negative effect of moisture on vessel size in floodplain, which does not occur in not-flooded lowland sites. We suggest that while tree productivity benefits from high water availability, the wood anatomical structure of Quercus robur is constrained by high soil water saturation in floodplain zone. In addition, the response of tree-ring widths to moisture availability is not uniform inside single stand, but subgroups of trees with completely opposite response coexist...
|
|
|
Spatiotemporal analyses of avalanches and their reconstruction by the mean of tree-rings of Norway spruce (\kur{Picea abies}) in the Giant Mountains National Park.
JANDOVÁ, Veronika
Various dendrochronological methods for avalanche reconstructions was applied on tree-ring records of dominant Norway spruce (Picea abies) in the Giant Mountains National Park. The individual growth chronologies from studied avalanche paths (Pramenný důl, Navorská jáma, Pančavská stěna, Velká Studniční jáma and Úpská jáma) proved that climate is the main driving factor of intra-annual variation of tree growth. Traumatic resin ducts are formed with delay up to 5 years. Combination of two and more tree-ring characteristics is suitable for reconstruction of avalanche events. I achieved to reconstruct undocumented avalanches. I conclude that dendrochronology is suitable tool for avalanche reconstruction; however, high pollutant emission highly reduced the potential of gained results.
|
|
|
Tree-ring chronologies of Norway-spruce on west-east longitudinal gradient in the mountain ranges of central Europe
Ponocná, Tereza ; Treml, Václav (advisor) ; Kolář, Tomáš (referee) ; Vejpustková, Monika (referee)
The Earth's climate system has recently experienced substantial warming which likely impacts temperature-limited communities close to their distribution margins. The alpine treeline ecotone represents upper distributional limit of montane/subalpine forests. This biogeographic boundary relies mainly on decreasing temperature with increasing elevation. Surprisingly the response of treeline ecotone to ongoing warming has varied a lot and the reasons of this variability are poorly understood. The aim of this dissertation thesis is the assessment of growth trends and tree ring response of Norway spruce (Picea abies[L.] Karst.) to climatic oscillations at treelines and montane forests of East-Central Europe. This dissertation deals with both inter-regional and intra-regional (aspect, elevation) variability of tree growth. The presented results are based on an extensive data set of growth curves for almost 1400 trees. All study sites revealed close relationship between tree ring widths and growing season temperatures as well as the temperatures of October preceding to ring formation season. The main site-dependent differences in growth trends and temperature responses were attributed to elevation, the effect of aspect was relatively less significant. At treelines between the Krkonoše Mts. and Nízké Tatry...
|
|
|
Remnant of forest at the transition from Late Glacial period to Holocene: dendroecological and palaeobotanical reconstruction
Moravcová, Alice ; Šamonil, Pavel (advisor) ; Rybníček, Michal (referee)
The remains from a sub-fossil pine forest burried in layers of peat deposits at the northern edge of the CHKO Křivoklátsko in the Central Bohemia is completely unique findings for the area of the Czech Republic. It offers new opportunities for palaeoenvironmental reconstruction and related climate changes during the Late Glacial and early Holocene epoch. The methods of dendrochronology and radiocarbon dating were used to date subfossil trees. The results of radiocarbon dating determined the existence of the forest in the period approximately 12,000 to 10,300 cal yr BP. The dendrochronological analyses revealed two continuous floating chronologies. The chronology RD4, which is long 200 years, originates from the Younger Dryas. The chronology RD6, 300 years long, originates from the Preboreal. The growth dynamics of the forest were reconstructed on the basis of the tree- ring analysis. Hydrological regime has been identified as a major disturbancy factor that influenced the growth of trees. This has been evident from synchronous phase depressions in the growth of synchronized tree-ring series. The high water table was the main cause of their extinction. This was in concordance with the results of macrofossils analyses. The effect of hydrological regime was largely influenced by microsite differences...
|
|
|
The morphology and activity of selected avalanche paths in the Hrubý Jeseník Mts. and the Králický Sněžník Mts.
Krause, David ; Křížek, Marek (advisor) ; Létal, Aleš (referee)
The occurrence of avalanche paths is usually frequent in alpine environment, but it is also present in mid-mountains such as the High Sudetes. The submitted master thesis is focused on avalanche paths in the Eastern High Sudetes. The morphometric analysis of 8 paths was accomplished to determine their characteristics and comparison with statistical verification. The dendrogeomorphological analysis and further geomorphological mapping was performed in 2 selected paths (Sněžná kotlina and Králický Sněžník) to cover their avalanche activity frequency and to find relationship between their activity and morphology. The results of this study show that there is a strong difference between two groups of avalanche paths in the Eastern High Sudetes. The Sněžná kotlina and The Králický Sněžník avalanche paths are longer and narrower than the other paths. They also have higher elevation difference. The comparison of these two paths performed by dendrogeomorphology indicates higher avalanche activity frequency in the Sněžná kotlina path, which was strengthened after strong avalanche event in 2004. It is assumed that the Sněžná kotlina path contains advanced avalanche landform, which is a long gully, probably also affected by debris- flows in the past. On the other hand the Králický Sněžník path is rather less...
|
|
|
Žatec and north-western Bohemia in the 2nd Half of the 10 Century
Čech, Petr ; Sláma, Jiří (advisor) ; Macháček, Jiří (referee) ; Moždzioch, Slawomir (referee)
The present work was written following a master thesis on the settlement and the shape of the early mediaeval agglomeration of Žatec in the 9th century. Subject of this dissertation is the processing of pottery from settlement features and from the 10th -century fortification. This enabled to study the development of the fortification system and changes of the settlement structure within individual settlement components. On the basis of excavations a relative chronology of the pottery and in accordance with the dendrochronological data a hypothesis on absolute dating has been presented. In view of this new chronology a new quantitative and qualitative analysis of information on the early mediaeval strongholds and hill-top settlements of the 9th and 10th century in the central and lower Ohře Region and in the Ore Mountain foothills was undertaken. A processing of the research on Drahúš stronghold has contributed substantially to this new perspective. The 1960s opinion on the affiliation of early mediaeval strongholds on the territory in question to the tribal territory of the Lučans, which should have been opposed to the Central Bohemian Přemyslid patrimony, based on the gathered information and its analysis could have been rejected. It was possible to comprise the evaluation of the excavation at...
|
|
|
Dendrochronological dating of the past avalanche events in the Krkonose Mts.
Tumajer, Jan ; Treml, Václav (advisor) ; Kociánová, Milena (referee)
Avalanches are important natural processes which shape the character of large mountainous areas. The reconstruction of their history has been performed on avalanche tracks in the Důl Bílého Labe Valley, Krkonoše Mts. through application of dendrogeomorphological methods. In total 101 trees from the area of 5 avalanche tracks were cored or cross-sectioned, which helped to identify 1253 growth disturbances (abrupt growth suppressions or releases, increases in tree-ring eccentricity, traumatic resin ducts, reaction wood, callus or determination of the tree death). The analysis spanning period from the 1859 led to the identification of 40 avalanche events, which prolong and complement written evidences of avalanche falls (avalanche cadastre). However, because of limitations of dendrogeomorphology (especially impossibility of dating of small events), these results have character of only minimal number of events. Strong influence of monthly snow melting and snow accumulation on initiation of events was pointed out through the statistical analysis of snowpack changes in relation to the reconstructed avalanche activity. Two main possible natural reasons for avalanche activity initiation were identified - vast spring snow melting and loading with fresh snow. The analysis demonstrates the potential of...
|
guest ::
