• Specifi c heat capacity is defi ned as the amount of heat that a kilogram of a given substance is required to absorb in order to (1967.) (DIP), Wood Handbooku (1999.) (WH) i radu Deliiskog (2012.) (DEL).Ključne riječi: specifi čni toplinski kapacitet, drvo, sadržaj vode, temperatura

a Wood extractives, especially polyphenols, have great influence on the xylem colour of many wood species, which affects the success of hydrothermal wood processing, such as wood drying. One such wood species is European black alder (Alnus glutinosa (L.) Gaertn.), which is prone to forming intense and uneven reddish-orange or reddish-brown discolourations immediately upon harvesting and processing. However, there is lack of published scientific data on the wood and bark extractives of black alder, as well as the most suitable solvents to extract them. In this work, total soluble extractives, phenols, and flavonoids have been quantified in the wood and bark of black alder. Furthermore, the influence of four different polar organic solvents and deionized water on extractives removal yields has been measured. It was found that the bark has much higher levels of extractives as compared to the wood. Furthermore, it has been found that the highest extractive yields were obtained by using methanol as the extraction solvent for all observed compound group classifications.

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SAŽETAK • Cilj je ovog rada pokazati mogućnost primjene računalnih programa za procjenu mehaničkih svojstava uslojenog drva i njihovu daljnju primjenu u kvantitativnim metodama. Analiza je ograničena na dva mehanička svojstva i na tri debljine furnirskih ploča (4,5; 12; 21 mm ABSTRACT • The aim of this paper is to demonstrate the possibility of applying computer programs for the evaluation of mechanical properties of wood, aiming at their further use in quantitative methods. The analysis is done of two mechanical properties and to three thicknesses of veneer plywood (4.5, 12, 21 mm). Mechanical properties that have been determined are fl exural strength and modulus of elasticity, both parallel and perpendicular to the outer veneer fi ber direction. Input parameters for the modeling were material properties with predefi ned values in the software used, and they were specifi c for Northern European hardwoods (PC-Bu) and material properties characteristic for Croatian area, which were achieved by experimental methods (EM-Bu). The results obtained were compared to the results of testing veneer plywood by destructive methods (FP-D). The analysis of the results

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