effect of subzero temperatures on FSP of cottonwood

This research investigates the thermal expansion and contraction of wood at varying moisture content values. The motivation for the research is to explain why less warp is noted and why lumber quality retention through the processing chain improves during the winter in Northeastern Europe and Northwestern Russia. It was found that subzero temperatures can depress the fiber saturation point (FSP) in wetwood, somewhat analogous to freeze drying during which the reduced atmospheric vapor pressure induces reduced equilibrium moisture contents. When wood is sawn in the frozen state, it is in a pre-shrunk and pre-dried condition. As such, by reasonable logical induction, subsequent thawing and drying have a significantly reduced ability to induce warp in lumber.