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Causes of vegetation heterogeneity of oak forests in Podbořansko region
Procházka, Michal ; Vojta, Jaroslav (advisor) ; Melichar, Vladimír (referee)
Thermophilous oak forests are a habitat characterized by a large diversity of vascular plants. In the case of open canopy woodlands, the diversity of the herb undergrowth is enhanced by the significant heterogeneity of the environment. It can be demonstrated for example at the Dětaň Chlum in neighborhood of the Doupovské hory Mts. However, it has not yet been fully known which natural characteristic have the most significant influence on the formation of such a diverse vegetation. One of the possible causes can be found in historical management. Therefore, this work provides some insight into the history of forest management in the Podbořany region based on archival materials such as Historical Forest Survey, Management Plans or Archive Maps. The obtained information is to a large extent surprising. It has been shown that coniferous stands with a long time of timber extraction have dominated the Dětaň chlum in the past. However, this contradicts the assumption that it is an ancient oak coppice, as suggested by the current appearance of vegetation with a high incidence of polycormones in the local nature reserve. To find out the environmental causes of the current heterogeneity of vegetation, I used the CANOCO statistical program to analyze the dependence of my own phytosociological data on selected...
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The origin of open canopy oak forests in Podborany region
Procházka, Michal ; Vojta, Jaroslav (advisor) ; Mayerová, Hana (referee)
The open canopy thermophilous oak forests are a phenomenon whose origin has not been completely clarified yet. However, they are a valuable source of a biodiversity caused by diversity of microstands which has an irreplaceable role in a landscape of the central Europe. Due to the appropriate protection it is desirable to understand the factors which caused this phenomenon. This review summarizes the current knowledge regarding the factors that support creation and preservation of open canopy oak forests in central Europe. In addition to abiotic factors such as small depth in the soil horizon, there is a large section primarily dedicated to human influence and now, mainly abandoned farming methods. Such methods include coppicing and wood-pasture. The question of the origin of open canopy oak forest is also discussed in the context of the history of farming in the Podborany region where we can still find a few open canopy oak forests. Powered by TCPDF (www.tcpdf.org)
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Productivity dynamics of herb layer in the thermophilous oakwood in the Nature Reservation Na Voskopě (Czech Karst) with respect to the solar radiation intensity
Mevald, Ondřej ; Černý, Tomáš (advisor) ; Josef, Josef (referee)
The Nature Reserve Na Voskopě is a special site where a long-term experiment was established in 2013, dealing with the switch of a long abandoned coppice back to its actively managed form. The project aims to examine the long-term impact of the proposed measures on the structure and diversity of plant species in herb layer especially in lighter woods at lower altitudes. The specific aim of this study was to examine the hypothesized crucial role of light conditions on the dynamics of plant biomass production in the undergrowth of such experimentally opened up thermophilous oak-dominated stand. A design was set up based on 40 permanent plots, where there were taken biomass samples from the herb layer in 2015. Further on, hemispherical images of forest canopy were photographed in the centre of each permanent plot. These images were evaluated in the analytical program WinScanopy, which calculates the amount of direct and diffuse radiation. The obtained datasets were evaluated by the regression analysis. The only decisive variable affecting the productivity of the herb layer turned to be diffuse radiation. The biomass data were also compared with light conditions sampled in the previous season (2014) as a part of ongoing experimental research. Season 2014 is characterized as a normal one and we managed to find a much stronger relationship between light conditions in 2014 and biomass productivity in 2015. Light conditions in season 2015 were significantly affected by the extremely dry and hot weather leading to strong defoliation of forest canopy. Still, we managed to demonstrate the positive impact of light conditions for the production of herb layer biomass. Weather extremes may also indicate an increase in biomass production in the next season, since a significant proportion of nutrients remained unused in the soil due to stopping the growth of vegetation. The current composition of the vegetation is very often determined by the extreme events in the abiotic environment occurring not long ago. Hemispherical images also proved as a very effective way to determine the light conditions, so it is also recommended to use for further research.
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