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Analýza příčin chřadnutí a odumírání bříz ve vybraných parcích hl. m. Prahy
Spěváček, Michal
The study is a comprehensive survey of silver birch trees (Betula pendula) located in four parks in Prague 6. In 2022, a dendrological survey of 112 trees was carried out. Selected manifestations of decline (dieback, sapwood, trunk swellings, trunk base wounds, exit holes, fungal fructification organs) were quantified and examined including laboratory tests. With the exception of Disculina betulina, no harmful non-native organisms were confirmed, but research on bacterioses and phytophthora was not conducted. It was concluded that the health and vitality of birch trees are significantly impaired across the surveyed parks and age classes. The decline of birch trees in Prague is a long-term problem resulting from various causes with drought probably playing a central role. Damage to the root and trunk base is also a crucial factor. The paper provides suggestions for improvement in its conclusion.
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Zhodnocení zdravotního stavu dřevin na vybraných plochách obecních lesů obce Chotovice (okr. Svitavy)
Buben, František
The bachelor thesis evaluates the tree health status in selected areas of the municipal forests of the Chotovice (district Svitavy). Monitoring was carried out at one-month interval from October 2016 to January 2018. Determined damages of trees were recorded and documented photos. Determination of microscopic types of damage took place in the MEDNELU laboratory. In total, 28 negative factors were found. Depending on the number of visits in which the species was found and the frequency of its occurrence, its significance was determined. Among the most important species that negatively affect the health status of woody species are insect pests European spruce bark beetle (Ips typographus) and Ash-bark Beetle (Hylesinus fraxini). The main fungal pathogens are Diplodia Blight Sphaeropsis sapinea, Fomes Root Rot (Heterobasidion annosum) and Ash Dieback (Hymenoscyphus fraxineus).
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Vliv různého typu poškození stromu na obsah nestrukturálních sacharidů u smrku ztepilého
Holasová, Veronika
The aim of the thesis was to investigate concentrations of nonstructural carbohydrates (soluble saccharides and starch) in various organs of damaged Norway spruce (Picea abies (L.) Karst.) trees. The damages of trees were girdling, xylem disruption, cutting off the roots and inoculation by Armillaria sp. The samples of the roots, xylem, bark with phloem and needles were collected in September 2013 and 2014. There were statistically significant differences in starch concentration in needles collected in September 2013; high starch concentrations were detected in girdled trees, while the lowest values achieved trees with xylem disruption. Another significant divergence was found in the concentration of soluble carbohydrates in needles collected in September 2014; the concentration of soluble carbohydrates in the control trees was significantly higher than in trees with cut roots. Other differences in the concentrations of nonstructural carbohydrates variously damaged trees and control trees were not statistically significant. Given the number of factors affecting the concentration of nonstructural carbohydrates -- especially financial and time factors -- they are not suitable as a simple and reliable indicator of tree vitality. However the data provide a deeper insight into the tree functioning after the damage. Inclusion of this information into the process based models will help to more accurate predictions of tree mortality.
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