National Repository of Grey Literature 13 records found  1 - 10next  jump to record: Search took 0.01 seconds. 
Extending the functionality of LaiPen
Trtílek, Jakub ; Šandera, Josef (referee) ; Hejátková, Edita (advisor)
The main goal of bachelor thesis was extending functionality of LaiPen LP 100 with voice recognition module, that would help to insert names of plants, while working with the device. Manual selection of vegetation is in the current version of the instrument barely used, cause of long time demands. Selecting, implementing and programming the voice recognition module EasyVR 2.0, was the topic of my work. Also the design of controlling menu and integration of the module to the LaiPen device. For the integration was necessary to design module, that would mediate communications between CPU and voice recognition module. The work includes also a design of I2C/UART convertor. For this design of the convertor was used microcontroller Max3109, that required to program main controlling functions.
Relationship between leaf biochemistry, physiology and specie's competitiveness in selected grasses of relict tundra in Krkonoše Mts.
Mamula, Petr Martin ; Lhotáková, Zuzana (advisor) ; Tylová, Edita (referee)
The Krkonoše (Giant Mountains) Arcto-Alpine Tundra is an area that is part of the Krkonoše National Park with a unique ecosystem and biodiversity. In history, this area was very fundamentally influenced by the intervention of man, who farmed here and thus caused the creation of today's rare matgrass (Nardus stricta L.) meadow ecosystem. Thanks to the low growth and sparse foliage of the matgrass, many other plant species grow in these matgrass meadows, which are often endemic and protected by the law. In recent years, however, the matgrass has been overgrown by other grasses, such as the hairy reed grass (Calamagrostis villosa J.F. Gmelin), which, due to its taller growth and dense canopy covering the surface, does not allow the growth of rare species such as matgrass. Therefore, the aim of this work was for matgrass (N. stricta) and three other selected species of grasses - tufted hair grass (Deschampsia cespitosa (L.) P. Beauv.), moor grass (Molinia caerulea (L.) Moench) and hairy reed grass (C. villosa), to identify, based on biochemical, structural and physiological foliar parameters, a parameter or a combination of parameters that could give competing fennel grasses a competitive advantage. Field research and collection of foliage samples, for subsequent laboratory processing, took place in...
Application of imaging spectroscopy in monitoring of vegetation stress caused by soil pollutants in the Sokolov lignite basin
Mišurec, Jan ; Kupková, Lucie (advisor) ; Pavelka, Karel (referee) ; Homolová, Lucie (referee)
Forests can be considered as one of the most important Earth's ecosystems not only because of oxygen production and carbon sequestration via photosynthesis, but also as a source of many natural resources (such as wood) and as a habitat of many specific plants and animals. Monitoring of forest health status is thus crucial activity for keeping all production and ecosystem functions of forests. The main aim of the thesis is development of an alternative approach for forest health status based on airborne hyperspectral data (HyMap) analysis supported by field sampling. The proposed approach tries to use similar vegetation parameters which are used in case of the current methods of forest health status assessment based on field inspections. It is believed that importance of such new methods will significantly increase in the time when the planned satellite hyperspectral missions (e.g. EnMap) will move into operational phase. The developed forest health monitoring approach is practically demonstrated on mature Norway spruce (Picea abies L. Karst) forests of the Sokolov lignite basin which were affected by long-term coal mining and heavy industry and therefore high variability of forest health status was assumed in this case. Two leaf level radiative transfer models were used for simulating spectral...
Modelling of snow interception in the spruce forest in the Ptačí Brook basin, Šumava Mts.
Míka, Dominik ; Jeníček, Michal (advisor) ; Šípek, Václav (referee)
Snow interception is one of the most important process of the hydrological balance of river basins. Measuring of snow interception is a very complex activity, therefore, models are frequently used to calculated snow interception from the vegetation structure and measured meteorological variables. A field research has been carried out in the Ptačí Brook basin in the Sumava Mts. to describe the canopy structure of the spruce forest using hemispherical images taken in the winter season 2020/21. The vegetation characteristics are essential for modelling of the snow interception. The mean Leaf area index calculated from the hemispherical images at the study plot reached 2.34 with the respective canopy closure equal to 86.16%. These values were further used as input values for the calculation of seasonal cumulative snow interception at the study plot for the winter season 2020/21. The original, more complex model was compared with two, less complex equations. Consequently, the model was applied to four consecutive winter seasons 2017-2021. The efficiency of the snow interception (a proportion of the intercepted snow to total snowfall water equivalent) ranged from 36.85% to 45.81% depending on the study season. The snow interception efficiency was considerably higher in the last winter season compared to...
Spatial snow distribution in locality with diverse forest structure in the Sumava Mountains
Švejdová, Klára ; Jeníček, Michal (advisor) ; Šípek, Václav (referee)
Snowpack is strongly influenced by several environmental factors. Besides meteorological and topographical conditions, vegetation structure plays an important role. The aim of this bachelor thesis was to assess how the canopy structure affects snow distribution. The snow depth and snow water equivalent (SWE) were measured in a selected location situated in the Kvildský potok basin in the Šumava Moutains during the winter season 2019. Canopy structure was described using Leaf Area Index (LAI) obtained from hemispherical images of the area. The degree-day method was used to calculate melt factors. The influence of vegetation was examined by using the correlation and regression analyses. Snow depth and SWE was significantly lower in forest sites than in the open area and in the forest disturbed by the bark beetle (Ips typographus). The influence of canopy structure was highest during snow accumulation and its importance decreased with time. The SWE variability was largest for last measurement during the melt phase. Melt factor calculated for period between last two field measurements was 2.3 mm∙řC-1 ∙d- 1 .
Variability in shortwave and longwave radiation in plots with different forest structure in the Sumava Mts. during snowmelt
Míka, Dominik ; Jeníček, Michal (advisor) ; Hotový, Ondřej (referee)
The bachelor thesis analyzed the variability in shortwave and longwave radiation at three locations with different canopy structure in the Ptaci brook basin in the Sumava Mts. The canopy structure was quantified by Leaf Are Index calculated from hemispherical images of the canopy. The shortwave and the longwave radiation were measured by radiometer at all locations. In the healthy forest, the average transmittance of the shortwave radiation was 6,5 % and did not change between individual study years. On the contrary, the transmittance of shortwave radiation increased in the damaged forest during study period. The transmittance relatively increased with increasing incoming shortwave radiation. The net longwave radiation was influenced by several factors which included not only the effect of the canopy structure but also transmittance of incoming longwave radiation and the total magnitude of the incoming solar radiation. The net longwave radiation was positive in the healthy forest, negative in the open area and changing from positive to negative in the damaged forest. The differences in the net longwave radiation lead to different dynamic of snowmelt. The net longwave radiation was correlated with incoming shortwave radiation (r = 0.68) in the healthy forest. The net longwave radiation gradually...
Forest health assessment in Czech Republic using Sentinel-2 satellite data
Lukeš, Petr ; Strejček, R. ; Křístek, Š. ; Mlčoušek, M.
This methodology aims to design a comprehensive system of nationwide assessment of the state of health of the Czech Republic based on Sentinel-2 satellite data analysis. The methodology addresses the entire process from the pre-processing of source satellite data using a novel approaches based on analysis of all-available satellite observations and their processing in the form of cloud-free mosaics of the Czech Republic using big data approach. In the next step, the products derived from cloud-free mosaics (vegetation indexes and other image analysis) are compared against extensive database of ground survey of forest health status (values of the leaf area index sampled as part of the development of the methodology - further denoted as LAI, database of tree defoliation ICPForests, airborne hyperspectral data acquired for selected study area, global forest losses database). For products with the best relationship to in-situ data, a predictive statistical model to yield LAI from satellite observations is developed. Forest health status is evaluated on the basis of yearly changes of the LAI values for cloud-free mosaics generated in the vegetation maximum. Individual pixels are classified into four health classes according to LAI growth rate or decrease in the observed period. The final assessment of the state of health is applied at the cadastral level, where each cadastral area is classified into four health classes based on the fraction of the lowest health status stands with significant LAI decrease to the total forest cover for stands up to 80 years of age
Application of imaging spectroscopy in monitoring of vegetation stress caused by soil pollutants in the Sokolov lignite basin
Mišurec, Jan ; Kupková, Lucie (advisor) ; Pavelka, Karel (referee) ; Homolová, Lucie (referee)
Forests can be considered as one of the most important Earth's ecosystems not only because of oxygen production and carbon sequestration via photosynthesis, but also as a source of many natural resources (such as wood) and as a habitat of many specific plants and animals. Monitoring of forest health status is thus crucial activity for keeping all production and ecosystem functions of forests. The main aim of the thesis is development of an alternative approach for forest health status based on airborne hyperspectral data (HyMap) analysis supported by field sampling. The proposed approach tries to use similar vegetation parameters which are used in case of the current methods of forest health status assessment based on field inspections. It is believed that importance of such new methods will significantly increase in the time when the planned satellite hyperspectral missions (e.g. EnMap) will move into operational phase. The developed forest health monitoring approach is practically demonstrated on mature Norway spruce (Picea abies L. Karst) forests of the Sokolov lignite basin which were affected by long-term coal mining and heavy industry and therefore high variability of forest health status was assumed in this case. Two leaf level radiative transfer models were used for simulating spectral...
An energy-based model accounting for snow accumulation and snowmelt in a coniferous forest and in an open area
Matějka, Ondřej ; Jeníček, Michal (advisor) ; Langhammer, Jakub (referee)
An energy-based model accounting for snow accumulation and snowmelt in a coniferous forest and in an open area An energy balance approach was used to simulate snow water equivalent (SWE) evolution in an open area, forest clearing and coniferous forest during winter seasons 2011/12 and 2012/13 in the Bystřice River basin (Krušné Mountains). The aim was to describe the impact of vegetation on snow accumulation and snowmelt under different forest canopy structure and density of trees. Hemispherical photographs were used to describe the forest canopy structure. Energy balance model of snow accumulation and melt was set up. For forest sites the snow model was altered for accounting the effects of the forest canopy on the driving meteorological variables of the snow model. Leaf area index derived from 32 hemispherical photographs of the vegetation and sky was used for forest influence implementation in the snow model. The model was evaluated using snow depth and SWE field data measured at 16 localities in winter seasons from 2011 to 2013. The model was able to reproduce the SWE evolution in both winter seasons beneath the forest canopy, forest clearing and open area with correlations to observations ranging from 0.16 to 0.99. The SWE maximum in forest sites is by 18% lower than in open areas and forest...
Assessing the impact of drought stress on winter wheat canopy by hermes crop growth model
Wimmerová, Markéta ; Pohanková, Eva ; Kersebaum, K. C. ; Trnka, Miroslav ; Žalud, Zdeněk ; Hlavinka, Petr
The main aim of this study was evaluate a drought stress effect on winter wheat development, growth (leaf area index), soil moisture and yields. Simultaneously, the ability of Hermes crop growth model to simulate drought stress response was tested. The field trial was established at Domanínek station (Bystřice nad Pernštejnem district, Czech Republic) in 2014. Mobile rain-out shelters for precipitation reduction were installed on the plots of winter wheat in May 2015. Results of this study showed that model is able to reproduce well a soil moisture content and to certain extent the drought stress for grain yields of winter wheat. Using the rain-out shelters (from 19 May to harvest on 6 August 2015), real winter wheat yields were reduced by 1.7 t/ha. The model was able to estimate the average yield with a deviation of 0.15 t/ha (6%) for no stressed variant. Model underestimated the yields for sheltered variant with a difference 0.67 t/ha (71%) on average against observed yields.

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