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Establishment and growth of spruces in reclaimed and unreclaimed plots on heaps after coal mining
Spurná, Veronika ; Frouz, Jan (advisor) ; Reif, Jiří (referee)
Coal is the most important raw material mined in our country. The mining acitivity creates huge impact on the landscape. The aim of the thesis is to compare the attachment of spruces on spoil tips created by coal mining and their growth during spontaneous succession and reclamation. The studied non-recultivated areas are overgrown with spontaneous vegetation consisting mainly of willow (Salix caprea), white birch (Betula pendula) and aspen poplar (Populus tremula L.). The reclaimed area only consists of planted Norway spruce (Picea abies). The density of localities, age and height structure, layout on terrain waves and distance from the edge of the dump were studied. Spruces were also mapped using GPS. The density of spruce vegetation on reclaimed areas is significantly higher than on succession, however, their growth is slower. On non-reclaimed areas, the growth of already attached spruces is significantly faster than on reclaimed areas. The results show a higher attachment of spruces on the slopes of the waves, especially on the northern leeward side, rather than in the troughs or on the peaks. The results show the possibility of undercutting succession areas with climax trees as a promising method of reclamation. Keywords: spruce, succession, reclamation, establishment of trees, density of trees
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Analysis of methods for determining wood moisture by non-destructive methods
Změlík, Jiří ; Zach, Jiří (referee) ; Vaněrek, Jan (advisor)
Subject of this bachelor thesis is the analysis and comparison of hygrometers considering their price, availability and applicability. Theoretical part compared available types of hygrometers based on their operating principle. Subsequently, resistance, capacitive and microwave portable hygrometers were compared in more detail. There were five reviewed hygrometers in total, with three of them capacitive and one of each resistance and microwave. The measurement was performed on beech and spruce trees at gravimetrically known humidity, ranging from extremely low to extremely high values (even out of bounds recommended by the manufacturer). The evaluation of the methods was performed according to the Saaty´s AHP method. Hygrometers were then selected by their optimization. After the experimental part, the suitability of individual methods was determined. The best method was capacitive, followed by resistance and the worst microwave method.
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The analysis of acoustic properties of innovative wood-based materials
Svojanovský, Jan ; Nop, Patrik (referee) ; Jirásek, Ondřej (advisor)
The content of this work is research of innovative wood-based materials in the acous-tic perspective. Basically, the goal is to determine the influence of the internal structure of the wood-based material on variables, which are sound speed, acoustic resistance, or acous-tic constant. In total were measured 15 samples, each one was made in a different way. Each sam-ple was weighted, and the length of its sides was measured. By using the ultra sonic timer, it was measured the time of the sound impulses, which go through the samples in all of their axes for the purpose of observation the influence the fibers on speed of sound in the materi-al. The next thing to do was to determine another magnitude, which describe acoustic of the material. All measurements were taken in room conditions (room humidity). Six of the sam-ples, which were randomly selected from those 15 samples, were measured once again after two weeks. In those two weeks were all the samples saved in air-conditioned place in which was the room humidity distinct lower. In the end all the samples were compared with each other and they were also com-pared with materials which are commonly used in production of musical instruments or acoustic components. Possible use in the music industry was assigned to each sample.
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Spatial throughfall variability in the spruce forest
Holata, Filip
In this study, we characterized a canopy by several methods and we found the best relationship between spatialvariation of canopy and throughfall volume. We validatedthe spatial variability of throughfall volumeandwe foundthat GFr is more appropriate parameter to use for more accurate estimation of throughfall volume than LAI and LPI.
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Study of quantitative parameters of Norway spruce needle structure under the effect of elevated CO₂ concentration and different irradiance
Kubínová, Zuzana ; Lhotáková, Zuzana (advisor) ; Urban, Otmar (referee) ; Gebauer, Roman (referee)
Zuzana Kubínová: Study of Quantitative Parameters of Norway Spruce Needle Structure under the Effect of Elevated CO2 Concentration and Different Irradiance, Doctoral Thesis, Prague 2019 Abstract Atmospheric concentration of CO2 is increasing, while its influence on plants is still not fully elucidated. Norway spruce (Picea abies L. Karst.) is an abundant conifer tree in European temperate and boreal forests, which behave as carbon sink in the global carbon cycle. The physiological response to elevated CO2 concentration may be interconnected with changes in leaf anatomy and morphology. Needle structure is also determined by other factors in addition to CO2 concentration, irradiance being the most important one. Thus, effect of irradiance was also included in our studies. The effects of elevated CO2 concentration and irradiance on Norway spruce needle structure were studied using new applications of well-established quantitative methods and novel methods enabling effective and unbiased analysis of needle structural traits. The General Procrustes analysis showed to be effective for needle shape on cross section comparison and the disector method proved to be suitable for chloroplast number estimates. The influence of elevated CO2 concentration and different irradiance on needle structure was studied at two...
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Using homogenization and nanoindentation for microfibril angle determination of spruce
Kucíková, L. ; Hrbek, Vladimír ; Vorel, J. ; Šejnoha, M.
This paper is concerned with the evaluation of microfibril angle of spruce. The microfibril angle is defined as an inclination of microfibrils from the longitudinal axis, the direction of lumens. It is well known and further supported by the present study that the microfibril angle has a great influence on the final mechanical properties of wood. This angle could be measured either directly using, e.g. polarisation microscopy, X-ray diffraction, infrared spectroscopy, or indirectly, as used in this study, by employing the nanoindentation measurements. Therein, the measured indentation modulus is compared with that obtained numerically using the anisotropic theory of indentation. The latter one depends on the entire stiffness matrix derived through homogenization and the searched microfibril angle. In view of the cell wall microstructure, the effective cell properties were found using the two-step micromechanical homogenization adopting both the Self-consistent and Mori-Tanaka methods.
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Forest management of the Dominican order in the Mimoň region
Nejedlý, Ondřej ; Foltýn, Dušan (advisor) ; Hnilica, Jiří (referee)
This thesis deals with the forest management of the Dominican Order in Mimoň area. Specifically, it focuses mainly on the area of Hamr nad Jezerem, in the years 1931-1938 and the last years of the active duty of the Directorate of the Dominican forest management in 1945-1950. The emphasis of the thesis is based on the description of the previously uncharted historical chapter of the Dominican order in this area, especially with regard to the economic activity of the forest administration in this given period and legal aspects of the whole issue with the acquisition, loss and subsequent efforts to return these properties. The Fund no. 37 in the Archive of the Dominican order, deposited in the 1st Department of the National archive in Prague, was used as the main source, subsequently supplemented by specialized and professional literature, an interview with the legal representative of the Dominican order in Prague in the case of restitution and also by few internet resources. KEYWORDS Dominicans, forestry, Hamr, Restitution, Hospitaller Order of Saint John, count Hartig, hunting, hunting area, logging, the first Czechoslovak Republic. Karl Waldstein, pine, spruce, lumbermill, Ministry of Agriculture, Military training area Ralsko, land reform, land reform review..
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Fine particles emitted from laboratory combustion tests
Hájek, Ondřej ; Šnajdárek, Ladislav (referee) ; Pospíšil, Jiří (advisor)
This bachelor thesis is aimed at fine particles emitted from laboratory combustion tests of biomass. The theoretical part of this thesis is about common features and usual ways of using biomass. After this broad chapter there is specifically described combustion and all its products including emission of gasses and fine particles. The main task of this thesis is about an experiment combining two analyses. First is the thermogravimetric analysis and the second is measuring size and number of fine particles in the range of 18 to 550 nanometers. The final chapter is about evaluation of measured results from 4 different spruce samples.
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Mechanical analysis of scarf joint fastened using cylindrical wooden dowel
Tippner, J. ; Milch, J. ; Kunecký, Jiří ; Kloiber, Michal ; Brabec, M. ; Sebera, V.
Traditional all-wooden woodworking joints play an important role in the behaviour of timber structures. These joints are also widely used when historically valuable constructions are being reconstructed and the connections are usually the masterpieces that testify to the high carpentry skills and knowledges of the overall mechanical behaviour. Within historical timber structures traditional carpentry joints were used while wooden dowel fixed mutual position of elements. Main aim of this study was to contribute to knowledge base about prediction and analysis of the mechanical performance of frequently used scarf joints made from spruce wood fastened using oak dowels. The objectives were to determine the joints' slip moduli and load-carrying capacity by means of theoretical and experimental approaches, in next to assess the mechanical behaviour of dowels through experimental investigation, and finally to perform a strain analysis of dowels. For these purposes, the optical technique employing three-dimensional full-field digital image correlation was used. The experiments were done on the full-scale specimens meeting the requirements of European standards (EN 383 and EN 26891), which were made from Norway spruce (Picea abies L. Karst.) and English oak (Quercus robur L.). The mechanical load consisted in tensile parallel and perpendicular to grain direction within the main components. The results of this study showed good correlation between theoretical approach based on based on Beam on Elastic Foundation theory and European yield model theory and experimental observations.
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