Differences in the Modal and Structural Parameters of Resonance and Non-Resonance Wood of Spruce ({ em Picea abies} L.)

Results of modal analysis and evaluation of cyclic inhomogeneity of wood and cell wall ultrastructure of a resonance and non-resonance spruce wood (Picea abies L.) are presented. The resonance wood came from a tree from Istebna, while the non-resonance wood came from a tree from the vicinity of Olsztyn. Modal analysis was made by a pulse excitation. The resonance and non-resonance wood differ in the fundamental modal parameters as well as in the number of vibrational modes. Macrostructural parameters of the wood samples were also measured. The angles of cellulose microfibrils in tangent walls of tracheids (microfibril angles or MFA) within individual annual rings were measured. The resonance wood was found to show high cyclic homogeneity of macro- and ultrastructural features.