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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...
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Effect of slope aspect on intra-annual growth of trees in the treeline
Zákravská, Šárka ; Treml, Václav (advisor) ; Ponocná, Tereza (referee)
This diploma thesis is focused on microclimatic differences at treelines on north-facing and south-facing slopes and their effect on tree growth. Thesis contains an overview of factors affecting development and timing of xylogenesis. The effects of slope orientation on treeline in relation to exposure effect are mentioned as well. The aim of the practical part of diploma thesis was to determine development, timing and the impact of temperature characteristics on xylogenesis of Norway spurce (Picea abies) on two localities with opposite slope aspect. Locations were situated in the Důl Bílého Labe valley, Krkonoše Mountains. Xylogenesis was studied using sections of micro-cores. Microcores were sampled every 10 days during the growing season. They were subsequently analyzed in dendrochronological laboratory. My results show that influence of air temperature recorded at the start of cambial cell division and the development of enlarging cells in the first part of the growing season. Climatic characteristics of both sites was similar, larger differences in temperatures were recorded at the beginning and at the end of the reference period.
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Historical position of alpine timberline in the Krkonoše Mts. derived from antique maps and photographs
Vágner, Tomáš ; Treml, Václav (advisor) ; Lipský, Zdeněk (referee)
The purpose of the diploma thesis is the analysis of alpine timberline shifts in the Giant Mountains between 18th and 21st century. The altitudinal position of alpine timberline is a sensitive indicator which reflects human impacts as well as the climatic changes. Methodical approach included the reconstruction of alpine timberlines from the old maps (published in 1765, 1851-52, 1879, 1906) and their comparison with the newer data, which were evaluated from a series of aerial photographs dated 1936 and 2002 (actualized 2005; data provided by supervisor). Data obtained from the old maps and aerial photographs (1936) were compared and verified with old photos and postcards from Giant Mountains. The average altitude of alpine timberline increased during the study period. The increase in elevation of alpine timberline is significant between 19th and first half of 20th century, e. g. in period when the human influence in Giant Mountains decreased. It is concluded that position of alpine timberline in Giant Mountains depended on human influence. Key words: tree line, alpine timberline, human influence, Giant Mountains
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Sensitivity of Scotch pine ring-width chronologies to climatic variables
Lehečková, Eliška ; Treml, Václav (advisor) ; Vejpustková, Monika (referee)
Presented master's thesis deals with the climate sensitivity of radial growth of Scots Pine (Pinus sylvestris) growing in the Protected Landscape Area Kokořínsko. The principal aim was to find out whether there are differences in the climate-growth response of pines growing on dry and mesic sites. To cope with that question tree ring cores were collected from stands on dry sandstones plateau and from stands near valley bottom with better water supply. Residual chronologies were developed and climatic factors limiting growth were identified using partial correlation analysis. The results show that pines on rocky sites respond positively to high precipitation during the vegetation season whereas trees on wetter sites react positively to high temperatures. In most study stands high February temperatures positively affect radial growth. Moving partial correlations analysis showed that the strongest responses to month climatic variables were stable over the studied period 1902 - 2009. Pointer years were determined and compared with precipitation and temperature anomalies in the corresponding pointer year, furthermore the effect of climate on number of trees with growth anomaly was studied using partial correlations analysis. Results of these analyses were in compliance with the previous findings. In...
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Applications of dendrochronology in hydrology and fluvial geomorphology
Šálek, Oldřich ; Treml, Václav (advisor) ; Svoboda, Pavel (referee)
Hydrological phenomena are natural processes that shape the landscape around us in the long-term and in some cases threaten our property or health. Dendrochronology is one of the methods of research of these phenomena and reconstruction of past hydrological events, that can be then used to predict and plan security measures in the future. The possibility of using a variety of dendrochronological methods in applied research, we can see in the meta-analysis of scientific studies available in electronic and printed form. The main finding of meta-analysis is a significant geographical disproportion in dendrohydrological survey. It also introduces a wide range of indicators, which are observed in various hydrological phenomena and also demonstrates application of dendrohydrological methods on specific studies.
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The importance of the forest continuity and fragmentation as a variable determining the diversity of beetles
Loskotová, Tereza ; Romportl, Dušan (advisor) ; Treml, Václav (referee)
Presented thesis examines the influence of two frequently discussed variables, forest continuity and forest fragmentation, on beetle diversity. An area of managed forests near Choceň was assessed. Longterm presence of local forest cover (minimum 240 years) can be documented by historical maps. Oak woodlands corresponding to the potencial vegetation were considered as continuous when older than 100 years. Those areas were compared with spruce forest. Fragmentation is understood to be a result of a conversion of species composition since 18th century until present. Other ecological and forest structural variables with possible influence on beetle populations were included. Out of the 38 completely described families of beetles were chosen into account. One defined taxonomically is represented by click-beetles (Elateridae) and the other group, saproxylic beetles, is defined by ecology. Their responses to variables of forest continuity and forest fragmentation were compared. Keywords: forest continuity, fragmentation, flight-intercept traps, biodiversity, saproxylic, beetles, Elateridae
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Spatial distribution and morphology of polygonal nets of frost and ice wedges pseudomorphs in the Czech Republic
Vohradský, Lukáš ; Křížek, Marek (advisor) ; Treml, Václav (referee)
Ice and frost wedges are a geomorphological phenomenon which is directly related to periglacial environment and permafrost (Murton, 2007). The presence of permafrost in the territory of the Czech Republic in the Pleistocene period is directly proven by polygonal nets of ice and frost wedge pseudomorphs, which are clearly visible in some remote sensing images. Among others, they can also be used as indicators of paleoenvironmental conditions for the period in which their recent forms originated and developed and for the period of their secondary infilling (Sekyra, 1958). The present thesis focuses on the spatial distribution and morphology of polygonal nets of ice and frost wedge pseudomorphs which were created in the territory of the Czech Republic at the end of Pleistocene and the beginning of Holocene. The analysis of the spatial distribution of polygonal nets was carried out with freely available remote sensing images provided by the GoogleEarth Pro application (Google Inc., 2011). The number of locations with a potential presence of pseudomorphs was 629. Out of these, 49 were subjected to a morphometric analysis of polygonal nets and their corresponding landscape. Statistical data analysis showed that the described polygonal nets of ice and frost wedge pseudomorphs in the territory of the Czech Republic...
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The morphology of avalanche paths
Krause, David ; Křížek, Marek (advisor) ; Treml, Václav (referee)
An avalanche path is a landform, that is being modeled by surface snow avalanches, debris flows and other slope processes. It consists of starting zone, track and runout zone. The submitted bachelor thesis is concerned with the characteristics of avalanche paths used in literature and generates their classification. The morphometric GIS analysis is performed in the Eastern High Sudetes. The measured vlaues of 16 avalanche paths from 6 sites are statistically processed and compared. The Sudetic paths are shorter but they have similar slope in comparison with paths in alpine environment. The spatial distribution of avalanche paths is bound to lee parts of the anemo-orographic systems. The aspect is predominantly southeastern, the slope is between 20 and 30ř and the length is usually between 200 and 400 m. The path lenght depends inversely on the slope of the starting zone. There is also a relation between the avalanche path morphology and the area of alpine tundra on the etchplain above the timberline, from where the snow is being blowed to the starting zones. Key words: snow avalanche, morphometry, Eastern High Sudetes, Altvatergebirge, Glatzer Schneeberg
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Past changes of alpine treeline ecotone, Hrubý Jeseník Mts.
Leštinská, Barbora ; Treml, Václav (advisor) ; Šenfelder, Martin (referee)
The aim of this study has been to analyse the spatial-temporal dynamics of the treeline ecotone formed by Norway spruce (Picea abies) as the dominant conifer in the Hruby Jesenik Mountains since the mid 20th century until the present in order to compare vertically connected sections of the timberline ecotone. Three features have been examined within the spatial and temporal context - the age structure, the spatial structure and the age/diameter growth. Dendrochronological methods have been employed to estimate the age structure. Moreover, the remote sensing and the GIS method have been used to detect the changes of the Norway spruce cover using the archive and actual aerial orthophotographs through their vectorisation and classification incorporating both spectral and spatial information as well as the knowledge base classification technique. The comparative analysis of the archive and actual orthophotographs has allowed to evaluate the spatial-temporal changes in the cover. The age and diameter growth relation has been established using the non-linear regression. It is established that the changes in the age and spatial structure are synchronous at all localities with a similar altitude. The younger age trees proportion is increasing with the growing altitude and the changes of the cover are largest in the...
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Site-dependent growth of Norway spruce, the Hrubý Jeseník Mts.
Boszczyková, Dita ; Treml, Václav (advisor) ; Janda, Pavel (referee)
Ring - wight chronologies of Norway spruce (Picea abies) from the twelve sites in the Hrubý Jeseník Mountains have been developed to study radial growth variability and a response to interannual climate variation. The sampled sites have been examined at three different elevations along the treeline ecotone according to the southwest and northeast aspect: in the closed-canopy forest at the lowest part of ecotone and in the tree groups at the lower and upper part of ecotone. The results have shown that the radial increment on the south-facing slopes has been slightly larger in the closed-canopy forest, particularly with the oldest trees. There have not been any differences in increment between the southwest and northeast slopes in the tree groups. The period of growth depression was detected during the 1970s and the 1980s at all sampled sites. This decline was probably a result of the effect of the air pollution combined with decreasing temperatures. An increasing trend in tree growth since the 1990s corresponds with the increasing temperatures and increasing nitrogen inputs at the sampled site. On each site, there has been a positive relationship between the current-year radial growth and the mean monthly temperatures in the growing season. In the individual months, there is a shift from the...
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