Within our simulations, where we identify a linear trend on a logarithmic scale (Figure ), it would appear at first glance that we do not see a clear moisture-induced glass transition. However, if we replot Figure on a linear scale (Figure ), this same ion and polymer diffusion information shows a clear transition at between 10-15% moisture content, where the diffusion goes from effectively zero to growing approximately linearly. Based on this simplified depiction of the plant cell wall and the observation of piecewise linear ion and polymer diffusion, we suggest that below 15% water weight the system behaves as though it were effectively static. Above that moisture threshold, internal motions become appreciable, and the material transitions to a more "rubbery" state rather than a glass. This observation of a moisture-induced glass transition, based on diffusion coefficients calculated from atomistic simulations agrees well with previously reported XFM experiments . Below this threshold, the diffusion for any permeant will be slow within a tightly bound arrangement of secondary cell wall biopolymers. However, once there is sufficient hydration, the diffusion approaches the maximum observed in an approximately linear fashion. Maintaining hydration above this transition point will be critical for applying penetrating treatments to woody biomass, and may contribute to vastly different cell wall diffusion measures across plant tissues . ). Ion diffusion in the plant secondary cell wall agrees well with previously reported X-ray fluorescence microscopy (XFM) experiments .