The thesis divided into four research topics dealt with an issue of the relation between silvicultural treatments and an amount of the bearing photosynthetically active assimilation apparatus quantified by leaf area index (LAI) in forest stands of an economically important tree species in the Czech Republic. In pure Norway spruce pole stands at the middle altitudinal zone, an effect of silvicultural treatments on the LAI and an efficiency of the photosynthetically active radiation (PAR; 380-720 nm) by foliage within the photosynthetic uptake was evaluated through both canopy production index (CPI) and leaf area effectivity (LAE), and the highest value of the LAI was achieved in a plot with the highest stand density. However, the highest efficiency of the PAR utilisation (CPI, LAE) was noted in the stand, which was tended by thinning from above. Thus, it was proved that not only the total LAI value but especially an efficacy of the leaf area reflecting sun and shade foliage ratio is the more relevant parameter for an evaluation of the effectivity of the thinning treatment. In a forest regeneration, the LAI can also be used for quantification of the regeneration process stage related to a growth dynamic of the natural regeneration. Besides that the newly developed device LaiPen LP 100 (PSI, ČR) for indirect optical LAI estimation was tested within this study. LAI values measured by LaiPen LP 100 showed almost same accuracy of the measurement and identical trends as world standard (LAI-2200 PCA; LI-COR, NE, USA); both at the stand level and the particular measurement point level. Within the study of the efficacy of the PAR utilisation by foliage in photosynthetic uptake expressed by radiation use efficiency (RUE) in pure, fully-stocked and not defoliated Norway spruce mature stands, it was found that mean air temperature most significantly affect annual and monthly values of the RUE with the significant linear relationship (R2 = 0.19; p < 0.05). In the spruce stands, the significant linear relationship (R2 = 0.85; p < 0.001) between an amount of the sequestrated carbon in the form of atmospheric CO2 molecules and the RUE was also proved. The research topic dealt with a seasonal dynamic of the LAI in selected pure and even-aged European beech and sycamore maple stands revealed findings that a culmination of the LAI is achieved within summer months (DOY 120-140) in the investigated stands. The period is the most suitable for estimation and mutual comparison of the LAI due to the stability of its values in investigated (but also in another deciduous) stands. In studied beech and maple stands, maximum LAI values were noted in the second half of June (DOY 170). General findings of underestimation of LAI values estimated by indirect optical methods compared to direct methods were also confirmed. In the last research topic, an effect of the stand age on the leaf area development was studied in pure, even-aged, and fully-leaved (not defoliated) forest stands of an economically important tree species (Norway spruce, Scots pine, silver fir, Douglas fir, European beech, pedunculate oak, and black walnut). Except for black walnut stands, significant linear relationships proving a decrease of the leaf area with increasing age of the stand were found. The relation between the leaf area expressed by effective plant area index (PAIe) and the age of stands was studied for monitoring of the leaf area dynamic within forest stands with a different age.

This Doctoral thesis is focused on research of usability hardwood that is not used in structural engineering nowadays. Analysis of known hardwood properties and its verification by experiment was made. Mathematic analysis using the PROMETHEE method was used for most suitable hardwood species selection in the Central Europe conditions. The most suitable hardwood – beech – was subjected for further tests: finger-joint load bearing capacity experiment and beech homogenous and hybrid glulam experiment. The test results are compared with the values from professional literature.

Bakgrund: Antalet datortomografiundersökningar (DT-undersökningar) har ökat kraftigt i Sverige och den kollektiva stråldosen till befolkningen blir allt högre. DT-undersökningar av buken är en av de undersökningarna som ger högst stråldos till patienten, därför är det viktigt att de endast görs när det krävs för att ställa diagnos. Därmed kan det vara relevant att undersöka huruvida antalet undersökningar också lett till ökat antal patologiska fynd hos patienter. Syfte: Undersöka hur många akuta DT-undersökningar med intravenös kontrast av buken som gjordes vid två sjukhus och hur stor andel av dessa som påvisade patologiska fynd. Metod: För att besvara syftet gjordes en kvantitativ retrospektiv studie där röntgenremisser och röntgensvar från mars 2013, mars 2018 och mars 2023 analyserades. Resultat: Antalet akuta DT-bukundersökningar med intravenös kontrast har ökat vid sjukhusen med i genomsnitt 49,5% mellan 2018–2023. Den mest markanta ökningen sågs i åldrarna 50–80 år. Vid Sjukhus 1 hade andelen fynd ökat från 57,5% i mars 2013 till 72,4% i mars 2023, samtidigt som andelen fynd vid Sjukhus 2 i stället minskat från 54% i mars 2018 till 46,3% i mars 2023. De vanligaste fynden vid de två sjukhusen var ileus/subileus, appendicit och kolecystit/gallsten/vidgade gallvägar. Könsfördelningen visade att något fler kvinnor än män genomgick akut DT buk med iv. kontrast, (Sjukhus 1: 54% kvinnor och Sjukhus 2: 55% kvinnor). Slutsatser: Det har vid båda sjukhusen skett en ökning av antalet undersökningar men utvecklingen av andelen fynd har gått i två olika riktningar. De vanligaste patologiska fynden som görs skulle kunna ställas med hjälp av andra modaliteter med låg eller ingen stråldos, såsom konventionell röntgen eller ultraljud. Ökningen av antalet akut DT-buk med iv. kontrast har medfört en ökad arbetsbelastning för röntgensjuksköterskor.