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Limity a možnosti přirozené obnovy buku lesního na LHC Kolowratské lesy
Zahradník, Tomáš
The aim of the thesis was to evaluate the possibility of natural regeneration of beech forest and its application to FMU Kolowrat forests. Selection of research areas was based on groups of forest types and by other characteristics such as different exposure, altitude and stocking of the stands. This thesis is based on the method of evaluation transect in forest stands. For each tree in the transect were measured these characteristics: height, the last increment of terminal, thickness of the root collar, shape and height of the deployment crown, number of lateral branches and their average game damage and other damage. Each of these characteristics were statistically evaluated. The result of this thesis shows that natural regeneration of beech is possible in whole evaluated area. From a biological and ecological perspective, is natural regeneration of beech convenient way for forest regeneration on those sites.
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Analýza tvorby dřeva buku lesního (Fagus sylvatica L.) na buněčné úrovni
Mikel, Jakub
The bachelor thesis describes the analysis of the wood creation of the europen beech wood (Fagus sylvatica L.) at the cellular level. The samples of three young trees were taken at weekly intervals, for two consecutive vegatation periods in 2013 and 2014. Subscriptions took place between 2013 and 2014, using the trephor. Permanent microscopic preparations were made from mikrocores and were observed using a light microscpe. This work explores the cambial aktivity and the proces of wood formation during the year season (from March to April). By using the light microscope, the beginning of cambial activity, its maximum activity and termination was recorded. Furthemore, the course of the cell differentiation in individual phases (radial expansion, the sekundary wall formation and lignification) were observed. Measured values of radial expansion were interleaved by the curve of the Gompertz function, which set the optimal model of radial increase during the year season. The date of maximum daily gain and average increase per day was determined from obtained data. Observing the cambial aktivity and the cell diferentiation in relation to climatic conditions will help us to understand the link between the wood formation and the influenc of the environment. The obtained results were compared with the professional literature.Formula clause:yes
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Využití mikrovlnné plastifikace dřeva při výrobě ohýbaných nábytkových dílců
Nováčková, Kateřina
This bachelor thesis is dealing with microwave plasticization for wood shaping and its potential utilization in furniture industry. European beech (Fagus sylvatica L.) specimens of dimensions 20 × 20 × 300 mm were sorted into 8 groups (each group consisted 15 specimens). Reference specimens (Ref1) were tested as oven-dried at room temperature, furthermore reference specimens (Ref2) were tested as oven-dried at 80 °C and last reference group (Ref3) was conditioned to fiber saturation point (FSP). Specimens of conventional, steam plasticization (Vp) were conditioned to FSP and heated at 100 °C for 1 hour. Microwave plasticization was carried out at 1,5 and 3,5 kW using continuous laboratory MW device All MW specimens were soaked in water in order to reach approx. 60 % of MC.Output moisture content (MC) of MW treated specimens was 20 % (MW1), 30 % (MW2, MW4) and 40 % (MW3). Moreover, additional specimens of dimensions 30 × 30 × 450 mm were used to up-scale its possibilities of use. These specimens were sorted into 2 groups (Ref and MW), each group consited 20 specimens. Effect of plasticization was measured by means of static 3-point bending test. Plasticity of wood was evaluated by modulus of elasticity (MOE), modulus of rupture (MOR) and deflection. Results of reference specimens confirmed influence of temperature and moisture content on MOE and MOR. Influence of moisture content (0 % and FSP) was found to be more significant and 65 % decrease of strength MOR and 40 % of MOE is reported. Steam plasticization, as a conventionally used method for shaping, led to increase of plasticity (decrease of MOE about 65 %) and deflection (70 %) when compared to Ref1. Significantly higher deflection (up to 1,5 mm) and increase of plasticity (MOE decreased about 72 %) was found for specimens plasticized by MW at 1,5 kW and 3,5 kW from initial moisture 60 % to output moisture 30 %. Based on results, it can be stated that microwave technology have similar effects on wood plasticity, when compared to conventional method wood plasticization – steaming. Results of present thesis confirmed high potential of MW plasticization for wood shaping. Reduction of time and safe energy might be considered as a great advantage for furniture production. Futher studies should be done in future in order to reveal effect of MW on structural changes, eventually to optimize process for specific shapes.
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Wood Extractive Compounds - Extraction, Chemical composition, Biological activity, Native durability =: Extraktivní látky dřeva: Extrakce, Chemické složení, Biotická aktivita, Přirozená trvanlivost /
Sablík, Pavel
Wood chemical composition research is of significant importance for various fields like wood-manufacturing, food and pharmaceutical industries. Much research work has been motivated by the fundamental knowledge that wood of some tree species demonstrate significantly higher native durability against biological degradation and therefore is much convenient to use in more demanding applications, e.g. in contact with soil or water. This important wood property was assign mainly to presence of extractive chemical compounds or secondary metabolites, produced by wood when heartwood is formed. The presented doctoral thesis aims to find the possibilities of how to utilize extractive chemical compounds found in Black locust (Robinia pseudoacacia L.) as treatment solutions. These can be used to increase the durability of low durable wood species. The experimental part of the presented thesis was carried out using the laboraties and equipment of the Mendel University in Brno, and their external laboratories of research centre in Útěchov. Paper 01 aims to establish methodology for extraction apparatus fexIKA. Describes mainly possibilities for quantitative gains of extractives when using various organic solvents. Within this papers research scope heartwood, sapwood and bark of Black locust were used as the source material. Black locust was choosen mainly due to its extremely high native durability, together with oak considered highest in Central Europe, and for longer term experimental plans and reason. The established methodology for primal solvents (acetone, benzene, cyclohexane, ethanol and distilled water) was the result of this paper. The influence of extraction inputs (particles size, solvent type and temperature) on quantitative and qualitative result of extraction process was the topic for research design presented in Paper 02. In the paper comparable results with literature and established fexIKA methodology were proven. Also the effect of the above mentioned inputs are described and extracted chemical content was identified using HPLC-HRMS technique. The possibility of utilizing chemical compounds obtained, based on Paper 01 extractive methodology, aimed for higher content of phenolic compounds according to Paper 02 results, were the topic of Paper 03. This research paper proves antifungal activity of Black locust (Robinia pseudoacacia L.) and African padauk (Pterocarpus soyauxii Taub.) extracts after impregnation into European beech (Fagus sylvatica L.) sapwood. This wood species is assessed as class 5 (not durable), with an average mass loss result after the durability test of untreated samples 43.6 %. Native durability of European beech wood was significantly improved after impregnation with extractives, mass loss resulted in average 12.7 %. This revalued treated beech sapwood into durability class 3. Paper 04 continues with a study of extractives retention in wood matrix after impregnation whilst introducing adjusted leaching tests. Despite standard EN 84, this research employed miniaturized Bravery wood blocks for impregnation and leaching tests, which were at the end shortened to 144 hours. In order to increase the biologicaly active chemical compounds retention in the specimens, heat treatment was used. The results of the experiment proved the significance between heat treatment and retention.
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