Moisture content has an effect on the biological decay of wood. The literature states that serious decay occurs when the moisture content of wood is above the fiber saturation point (FSP), which is the measurement of the moisture content of wood when the cell walls are saturated and the cell cavities free from water (average 30%). We can chemically modify wood hydroxyls by various treatments (i.e., acetylation, isocyanates, and epoxides) which result in the lowering of the FSP. If we modify the availability of water in the cell wall, we can reduce or eliminate biological degradation. So is biological protection as simple as removing a water molecule at the glycosidic hydrolysis site required by the degrading enzyme? Investigations are underway to chemically modify wood and fiber samples and evaluate them biologically by the soil block test, as well as by the FSP and the equilibrium moisture content (EMC). EMC is the moisture content of wood at any given relative humidity and temperature. Potential correlation between moisture exclusion and biological protection will be discussed.