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Paleoclimatic proxies for the Upper Holocene in Central Europe
Heglasová, Veronika ; Treml, Václav (advisor) ; Nývlt, Daniel (referee)
This thesis summarizes findings of the Central European climate evolution during the Late Holocene and approaches to studying the paleoclimates. Indirect sources of evidence about a climatic variable, i.e. proxy data, are used to infer quantitative estimates of temperature or precipitation and can be subdivided into several categories: tree rings record both low- and high-frequency variability of climate with annual resolution; biological (and palynological) proxy data show evidence of longer-term climate changes which are deduced from changes of assemblages/taxa and their ecological preferences. Sedimentary chemistry, including stable isotopes 18 O a 13 C, maintains information on environmental conditions at the time of origin and deposition of sediment (thanks to fractionation and other processes); natural archives are complemented with documentary data which capture the fluctuations of climate up to monthly resolution and also extreme events. There is 44 quantitative paleoclimatic reconstructions in the Central Europe that employ the aforementioned proxy data, although the majority of research articles investigates only approximately the past one thousand years. The temperature and precipitation are reconstructed in the area of the Czech Republic for the past ~600 years. Decadal variability of...
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Selected approaches of climate-growth relationship determination of trees
Pekař, Ondřej ; Treml, Václav (advisor) ; Ponocná, Tereza (referee)
Presented bachelor thesis describes the use of tree-ring widths in dendroclimatology and main approaches of climate variables reconstruction. It reviews the basics about climate influence on tree- ring fromation and extraction of climate signal from tree-rings. Main standartization methods were used to develop 26 standard and residual chronologies from adjusted and not adjusted tree-ring series coming from high-elevation Norway sporuce stands. Chronologies were compared in terms of correlation with summer temperatures. The best correlated temperature variable were the June-July temperatures both for standard and residual chronologies. Tree-ring width chronologies were scaled to observed June-July temperatures. Based on comparison of scaled and real June-July temperatures, negative exponential function and RCS method appear to be the most suitable to preserve both high and low frequency climate signal. Key words: Dendroclimatology, tree-rings chronology, standardization, climate reconstruction
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Spatial distribution snow cover in alpine forest-free area, Krkonoše mts.
Klivanová, Lucie ; Treml, Václav (advisor) ; Jeníček, Michal (referee)
Snow is a an important factor in alpine forest-free area and character of snow accumulation and degradation affect soil water availability; snow's insulation, soil temperature variations and regelation. Snow can influence flora and fauna, evolution of soils and occurrence of periglacials forms. This thesis deals with the distribution of snow cover and influencing factors of spatial pattern of snow depth.. The research of snow cover distribution was based on periodic field measurements of snow depths in winters 2009/2010 and 2010/2011. For evaluation and interpretation of measurements, data were statistically processed in programs ArcMap and STATISTICA 10. Based on statistical analysis, series maps of snow cover distribution was produced. Altitude, curvature, heat-load index, the orientation of the locality relative to the east (folded aspect with 0ř towards the east) and percentage of graminoid vegetation were the most important variables explaining snow depth. Furthermore the results of terrain measurements confirmed distribution snow cover of previous works. Key words: snow cover distribution, depth of snow, physical-geographical factors, modelling and measurement of snow cover, regression analysis, alpine forest-free area, east Krkonoše mountains
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Effect of altitude on intra-annual growth of trees in the treeline ecotone
Kašpar, Jakub ; Treml, Václav (advisor) ; Gryc, Vladimír (referee)
RESUMÉ Tato práce se zabývá vlivem teplotních poměrů na intra-anuální růst smrku ztepitélo (Picea Abies (L.) Karsten) na alpínské hranici lesa v Krkonoších ve vegetačních sezónách 2011 a 2012. Monitoring probíhal na dvou lokalitách na jižním svahu Luční hory. První lokalita se nacházela v nadmořské výšce 1310 m n. m., přibližně na horní hranici zapojeného lesa, druhá pak v nadmořské výšce 1450 m n. m., ve stromových skupinkách nad horní hranicí lesa. Mezi lokalitami byl pozorován poměrně vysoký vertikální teplotní gradient jak u teplot vzduchu (1,2 - 1,7 řC), tak u teplot půdy v hloubce 10 cm (0,8 - 1,2 řC). Teplotní rozdíl mezi lokalitami se pak projevil v nižším pozorovaném přírůstu na výše položené lokalitě. Pozorované počátky kambiální aktivity se pohybovaly od 26. 4. do 21. 5. Začátek kambiální aktivity je ovlivněn množstvím sněhové pokrývky akumulované na lokalitách v průběhu zimy a s tím souvisejícím datem jejího odtátí, teplotami půdy a teplotami v přízemní vrstvě atmosféry. Délka kambiální aktivity se pohybovala mezi 55 - 77 dny, přičemž její délka byla nižší na výše položené lokalitě. Diferenciace buněk nastala bezprostředně po počátku kambiální aktivity a trvala od 111 do 132 dní. V porovnání sledovaných růstových sezón vyšla lépe růstová sezóna 2012, ve které byl průměrný přírůst stromů vyšší na...
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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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