The importance of seasonal differences in the cellulose microfibril angle in softwoods in determining acoustic properties

The influence of the micro- and mesoscopic structure of wood cell walls on the acoustic properties of softwood was investigated in a synchrotron X-ray microbeam diffraction experiment with particular attention to the seasonal differences in crystallographic features. A multiple regression analysis was performed for data from 12 different softwood species in order to determine the dependence of longitudinal relative Young's modulus (E/rho) and loss tangent (tandelta) on seasonal cellulose microfibril angles (MFAs), crystal width of cellulose microfibrils etc. We conclude that a low MFA in both latewood and earlywood yields high E/rho and low tandelta, which is an attribute of wood used as violin or piano soundboards. Among the softwood species we characterized Sitka spruce best fits this criterion. (C) 2002 Kluwer Academic Publishers.