Application of the second order Fourier transformation on the density function of sugi trees = A másodrendű Fourier transzformáció alkalmazása a sugi faanyag sűrűségfüggvényére

The juvenile wood has features that distinguish it from the older, more mature wood of the bole. Juvenile wood is an important wood quality attribute because, depending on species, it can have lower density, has shorter tracheids, thin-walled cells, larger fibril angle, and high – more than 10% – lignin and hemicellulose content and slightly lower cellulose content than those of mature wood (Zobel and van Buijtenen 1989, Zobel and Sprague 1998). Wood juvenility can be established by examining a number of different physical or chemical properties. Juvenile wood is not desirable for solid wood products because of warpage during drying and low strength properties, and for producing high stiffness veneer, either (Zhu et al. 2004). Fourier transformation is an extremely useful mathematical tool used in the quantitative analysis of many physical processes. Fourier transformation can be represented as a series of sine and cosine functions. The main purpose of the experimental work described in this report was to develop a new method to determine the demarcation between juvenile and mature wood by means of Fourier analysis of the density distribution curves.