Popis v originálním jazyce:
Wood properties play an important role in truss mechanics and durability and therefore a selection of high-quality material is one of the basic steps in traditional carpentry technique of restoration of valuable historical constructions. From this perspective, simple and reliable methods for assessment of standing trees, logs and timber are searched. Do we have a reliable tool for prediction of timber quality in-situ? Are the harvesting period and timber storage significant factors influencing in quality of structural wood? Forest stands in Bohemian-Moravian Highlands with optimal ecological conditions for Norway spruce was selected. 28 standing trees were sorted and assessed by visual methods and device supported methods. Consequently 17 trees were felled, sampled, milled to logs and again tested by various devices. All logs were processed to make 68 beams (20x24x240 cm) by traditional carpentry way or machine milling. Traditional ways of wood treatment in water were tested too. The 68 beams were tested by frequency-resonant method in the course of almost 2 years. 24 trees were also felled during 3 different seasons. These trees were felled 7 days before full moon or 7 days after full moon. The 47 beams made by the traditional carpentry process came from these trees. Wood densities, annual widths, sound velocities, dynamic modulus of elasticity, micro-drilling and indentation resistances were measured, and visual assessment was carried out. The differences and relationships between properties were statistically tested to determine significance of manufacturing parameters and reliability of used methods to predict properties at several levels of wood processing, and also to describe the influence of harvest period or timber treatment to quality and properties.