The hypothesis that the longitudinal moisture content profile follows the s
hape of the sorption isotherm under steady-state diffusion condition was co
nfirmed. This phenomenon was explained in terms of the unrestricted flow of
water vapor from the lumen of one vessel element to the lumen of the next
vessel element. Despite the assumed high vapor transport efficiency of the
vessels, other cell types were believed to contribute substantially to long
itudinal moisture movement. The diffusion coefficients of three different h
ardwood species were found to vary with moisture content.