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Response of tree rings and NDVI of Central-European conifers to extreme climatic events
Mašek, Jiří ; Treml, Václav (advisor) ; Šilhán, Karel (referee) ; Piermattei, Alma (referee)
Terrestrial ecosystems, mainly forests are important sinks of atmospheric carbon with high year-to-year variability driven by moisture availability. Trees store carbon in various compartments of the biomass, namely in stems, roots, and leaves. In this doctoral thesis, I investigated climate-growth responses of stem biomass (represented by tree rings) and leaf biomass (represented by normalized difference vegetation index; NDVI) of Pinus sylvestris and Picea abies in temperate forests of Czechia. I was interested in (i) general climate-growth responses and specifically, in reactions to drought and (ii) topographical factors influencing these responses at various spatial scales. We demonstrated that climate-growth responses of both species' tree rings in the lowlands revealed a significant positive and negative influence of moisture and temperature, respectively, while in higher elevations the responses were opposite. At a landscape level, the topography of relief modulated responses of Pinus sylvestris tree rings, while at the large-scale level, the geographical position and elevation (temperature gradients) were the main factors for both species. Responses of NDVI were slightly weaker compared to tree rings and did not show the influence of topography at any scale probably because vegetation...
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The influence of climate on the radial growth of Scots pine in the northern Scandinavia
Tomeš, Miroslav ; Treml, Václav (advisor) ; Šefrna, Luděk (referee)
The presented master's thesis deals with the influence of climate on the radial growth of Scots pine in the northern Scandinavia. Trees growing at the polar treeline are sensitive to environmental changes, and therefore their wood is used to study growth responses to ongoing climate change. During the period of the 20th and the beginning of the 21st century, air temperatures and precipitation sums were correlated with tree rings and dendroanatomical data of Scots pine from northern Finland. It was found that the widths of the tree rings had a slightly increasing trend during the observed period. Within the framework of the correlation relations, the controlling influence of the air temperatures of the current July on annual increments was confirmed. Thanks to the higher temperatures of the summer season, wider tree rings were formed. In addition, May and summer precipitation have been shown to be important for the final width of the tree ring. The currently often discussed problem of decoupling the tree ring chronology curve from rising summer temperatures ("divergence problem") was not clearly observed in this work. In order to evaluate the dendroanatomical parameters, the tree rings of the studied individual were divided into four sectors with a similar number of cells in the radial file. During...
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Use of laboratory and image spectroscopy to evaluate drought resistance of Scots pine and to distinguish its ecotypes
Raasch, Filip ; Kupková, Lucie (advisor) ; Potůčková, Markéta (referee)
The aim of this study was to propose a non-destructive method for measuring Pinus sylvestris seedlings, to determine whether water stress would be evident in laboratory spectra of pines, to compare whether the response of pines would differ by ecotype, and to investigate whether two ecotypes of Pinus sylvestris could be distinguished using laboratory and image spectroscopy. For these purposes, hyperspectral images of seed orchards from August 2020 were processed and a three-month laboratory experiment was conducted, in which stress from water deficit was induced in two-year-old pine seedlings from the upland and hilly ecotypes. Spectral data were analysed using mixed statistical models, analysis of variance, principal component analysis, training of supervised pixel classifiers, vegetation indices, and linear regression. Based on the analyses, it was found that water stress can be detected in severely stressed Pinus sylvestris seedlings. The most sensitive spectral bands to water content were observed in the region between 1000-2500 nm. The initial response to water stress did not differ by ecotype, but a faster recovery was observed at the upland ecotype after the period of draught. The two Pinus sylvestris ecotypes were distinguished with high accuracy from both laboratory and image spectral...
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Ochrana lesa před chroustem maďalovým v gradačním území Moravské Sahary
Jarošová, Veronika
The aim of this master´s thesis was the evaluation of options that should lead to the elimination of the harmful effects of the white grubs of Melolontha hippocastani to the gradational area of Moravian Sahara (part of forest maintenance LS Stážnice, the Bzenec district). The effectiveness of chosen preparations (Force 1,5 G and Actara 25 WP) on the white grubs of Melolontha hippocastani was observed and conducted under controlled conditions in the ´container experiment´ with 380 seedlings of Pinus sylvestris. This experiment was repeatedly conducted five times over a period of 3 years. The results show that the most effective preparation against the white grubs is Actara 25 WG (200 up to 400 g/ha/600 l water) in the form of watering. This preparation in the form of spraying was ineffective. Inconsistent results were reached with the preparation Force 1,5 G. At the same time, the vertical movements of white grubs during their development stages in the soil were being observed over the period of 2015–2018. This observation took place in the drill holes of the following proportions 50 x 50 x 60–140 cm. The results confirmed that the depth of wintering of the white grubs and their movements during their vegetative state depends on the soil´s temperature and moisture, and the available sources of food to the current instar of the white grub.
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Canopy effect on the Scotch pine regeneration in understory
Kostohryzová, Aneta ; Ulbrichová, Iva (advisor) ; Bílek, Lukáš (referee)
The Pinus sylvestris natural regeneration growth and site characteristics effect were evaluated in the area of VLS ČR, s. p. divize Mimoň-Doksy in september of 2015. The dendrometric parameters of seedlings as listed: the total height, the diameter, the last 5 years height increment, the crown diameter, the quality and vitality of plants and the branch angle) were measured at nine plots. Also microsite characteristics, such as: herbal layer composition, light conditions, litter horizons and distance to the nearest adult tree) were noted at these sites. The 416 seedlings were measured in total. The main site characteristic with significant effect on the mean increment was direct photosynthetical radiation (r = 0,47). Other significat factors were the total and the diffuse photosynthetical radiation, the canopy and the amount of small bushes in herbal layer. There can be also concluded that good light conditions have statistically significant effect on the quality of seedlings. Influence of other site characteristics was not statistically significant.
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Environmental factors effect to the Scotch pine seedlings survival
Pourová, Marie ; Ulbrichová, Iva (advisor) ; Janeček, Vladimír (referee)
The survival and mortality of the Scots Pine (Pinus sylvestris) seedlings during the vegetation season of 2015 are evaluated in the thesis. The seedlings in greenhouse conditions in Truby were exposed to water deficiency, three variants of shading and simultaneously to environmental temperature, which, due to weather, was extraordinary high at the time of the experiment.
The highest number of grown seedlings from the seed material from Plasy was 89 % from the total of 224 outplanted ones, namely in conditions of mean shading and slightly reduced watering. The highest mortality of the seedlings was found in unshaded environment with slightly reduced watering, in mean shading with the second lowest watering and in the highest shading with the second lowest watering, the mortality was 100 % there. The seedlings from the seed material from Doksy were much more hard put to it. The seedlings grew only in four cases in unshaded environment with the highest watering (4 % from 224 outplanted ones), in mean shading with the highest watering (38 %) and in the environment with the highest shading together with the highest watering (68 %) and slightly lowered watering (1,3 %). In all cases the seedlings mortality was higher than 70 %.
The lowest number of grown seedlings occurred in unshaded environment and between the variants with mean and high shading, there was only a small difference. The results were strongly affected by extraordinary warm vegetation season.
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