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Savci jako škůdci na ovocných dřevinách a v sadech
Benešová, Kateřina
The bachelor thesis deals with the negative impact of wild mammals on fruit trees and orchards. The main aim is to find out which mammal species are harmful to fruit trees and what types of damage they cause. Based on the literature, it is then possible to derive solutions to effectively protect against this damage. In addition, a questionnaire survey can also be used to address the problem. Damage to fruit trees is most common from rodents (Rodentia), even-toed ungulates (Artiodactyla) and hares (Lagomorpha). Several important factors influence the impact of these mammals on fruit trees. Rodents cause the most damage at times of peak abundance, so regular monitoring is needed. Currently, there is a growing interest in biological control of mammals, where no chemical products are used. However, due to its immediate result and ease of application, chemical control still prevails.
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Kvantifikace odchylek objemu dříví při jeho měření harvestory a rozbor jejich závislostí na vybraných faktorech
Lesák, Josef
This thesis focuses on the problems with determining the dimensions of the timber during the processing with the harvesters. This study discusses all the possible variations in measurements, their origin and a resulting impact on the volume of the timber. Furthermore, this thesis describes other methods of measuring timber, such as manual measurement or measuring by sensing proportions of the timber with a saw measuring frames. The emphasis is on the variances in the calculation formulas, particularly focused on the differences in setting the reading bark. The research is supported by two measurements in the field, more specifically on the spruce vegetation. During these field measurements we performed the cuts with harvesters on the amount of 6 trees which were subsequently transported to the sawmill for the standard electronic checks. The log performed with the harvesters were afterwards measured twice for the purposes of precise volume measuring.
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Phytopathogenic fungi causing necrosis of Acer pseudoplatanus bark
Kelnarová, Ivana ; Koukol, Ondřej (advisor) ; Černý, Karel (referee)
Bark necrosis is a symptom of variously serious diseases caused by various pathogens. Sycamore is relatively susceptible to bark necrosis, especially trees weakened by stress such as climatic extremes or anthropogenic pollution. Causal agents are Ascomycetes and also Peronosporomycetes of the genus Phytophthora. Degree of pathogenicity is variable, ranging from local necrosis to cankers invading cambium resulting in death of the host. Pathogens can be classified as opportunistic (Cryptostroma corticale), weak (Prosthecium pyriforme) or obligate (Eutypella parasitica). Saprophytes decomposing dead tissue can also be isolated from necroses. To prove non-pathogenicity of these species inoculation experiments on the host are needed. Mycophagous fungi may grow in necroses as hyperparasites (Acremonium sp.). Various species of invertebrates search for necroses as a source of food and shelter. Several small mammals were observed feeding on bark necroses. Their role in spreading spores and initiating a gateway for infection is also considered.
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