National Repository of Grey Literature 5 records found  Search took 0.00 seconds. 
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...
Dendroclimatology of arctic shrubs
Lexa, Martin ; Treml, Václav (advisor) ; Vejpustková, Monika (referee)
Thesis focuses on the influence of climate on microscopic structure of anatomic features in juniper wood. Dendrochronology as a method reaches its limits in the Arctic regions. Insufficient network of meteorological stations providing sufficiently long series of climatical data is the reason of increasing interest in studying Arctic shrubs, which can occur even beyond the latitudal forrest line. Thirty-three discs from juniper shrubs were collected in Gangasdalen valley on the banks of Jarfjord fjord in the August 2014. The master chronology was developed from 26 cross-dated samples. Eight carefully chosen samples were used for microscopic measurement of wood anatomic features during the reliable period of the main chronology using WinCell Wood Cell Anatomy software. Lumen area, wall thickness, number of cells and tree ring (its part) width were measured for both whole ring, and for earlywod and latewood. It was found that ring width does not necessarily have the highest dependency on climate and therefore may not always be the best climatic proxy. The highest dependency reached the number of cells, which was generally positively correlated with summer temperatures. On the other hand, lumen area shows the lowest dependency on climate.
Klimatický signál v letokruhových chronologiích borovice kleče
Samusevich, Alina ; Treml, Václav (advisor) ; Vejpustková, Monika (referee)
Pinus mugo Turra (sensu lato) is a prostrate shrub growing above the alpine timberline in the mountain ranges of Southern, Central and Eastern Europe. It is well adapted to the harsh alpine environment creating different mechanisms for survival. The research was carried out in Krkonoše Mountains on base of Pinus mugo individuals compared with Picea abies trees. Samples from shrubs were gathered using serial sectioning from four sites in different elevations located on Sněžka Mountain and Smogornia Ridge. Further analysis of the sampled material was made with the help of different detrending methods to see which method will return the best growth response to climate parameters. RCS detrending and detrending via simple averaging reflected the best climate signal contained in dwarf pine chronologies. The advantage of these methods is based on their ability to reflect growth conditions of the particular site. Upper sites showed significant correlations with temperatures of the growing season, while on lower sites the signal was quite unclear. The amount of precipitation plays the significant role on shrub growth during the vegetation period (especially July month) and early spring when water is very important for growth initiation. Upper Pinus mugo sites showed high sensitivity to droughts, especially...
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...
Chřadnutí lesních porostů na LS Jablunkov – určení komplexu příčin poškození a návrh opatření pro revitalizaci lesa
Výzkumný ústav lesního hospodářství, v.v.i., Strnady ; Vortelová, Lucie ; Vejpustková, Monika ; Vícha, Zdeněk ; Pešková, Vítězslava ; Oceánská, Zuzana ; Novotný, Radek ; Novák, Jiří ; Lachmanová, Zora ; Kacálek, Dušan ; Hellebrandová, Kateřina ; Dušek, David ; Balcar, Vratislav ; Slodičák, Marian ; Soukup, František ; Šrámek, Vít
Část lesní správy LČR s.p. Jablunkov je postižena žloutnutím smrkových porostů, které vede k postupnému usychání a odumírání jednotlivých stromů. Závěrečná zpráva shrnuje výsledky řešení projektu v letech 2006 až 2008. Řešení se soustředilo na několik oblastí, které odpovídají kapitolám zprávy. Posouzení zdravotního stavu lesních porostů mělo za cíl posoudit rozsah poškození, jeho prostorové rozložení a jeho dynamiku. Posouzení výživy porostů se opíralo o chemické analýzy půd a asimilačních orgánů ve vybraných porostech různého stupně poškození. Znečištění ovzduší bylo hodnoceno měřením pasivními samplery GRADKO, byla měřena úroveň depozic na volné ploše a v lesním porostu buku a smrku. Do projektu bylo zahrnuto i hodnocení dlouhodobého vývoje meteorologických parametrů - teplot a srážek. na plochách byla sledována aktivita biotických škodlivých činitelů: hmyzu i dřevokazných hub a byla hodnocena úroveň mykorhiz. Závěrečná kapitola obsahuje návrh pěstebních opatření.

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