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Trees are subjected to multiple environmental mechanical loads and adapt the mechanical properties of their stems to an environment changing over time. Wind is one of the most important (Timell, 1986a). Wind loading can cause mechanical failure making the tree worthless in a commercial sense. A substantial amount of research on predicting wind throw and wind damage risk for commercial species has been conducted (Ancelin et al., 2004; Peltola et al., 1999; Mayer et al., 1989; Gardiner et al., 2000; Dunham and Cameron, 2000). These models do not investigate the structural failure within the tree, but attempt to identify how likely failure is to occur in a particular environment. Wind also has less obvious effects. Continued wind loadings from a prevailing direction can cause compression wood production on the lee side of the pith in order to compensate for this loading (Timell, 1986a).  One way of investigating the time phenomenon is the use of mathematicalmodels, such as finite element  models. However because of the size of the tree, modelling an entire tree from the molecular level is infeasible, so homogenisation is used. This is the case for a number of current problems in plant biophysics. In order to use finite element methods experimental data is required for parametrization. While MFA controls the stiffness of the cell wall, basic density measures the amount of cell wall in the tissue. Therefore overall mechanical wood properties rely on both features. For a more detailed description of the TRP of MFA and density or these modelling and experimental attempts see ---Chapter 1---.