Abstract: Heat transfer of wood with the moisture content below the fiber satuation point was analysed by the liner theory of non-equilibrium thermodynamics. The results showed that diffusion of water vapour and bound water contributed to the heat transfer and thermal conductivity of wood consisted of one coefficient of heat conduction and two equivalant coefficients arising from the diffusion of water vapour and bound water. The expressions of three coefficients were derived by extended Siau's theory on heat transfer of wood and the principle of water sorption and fluid diffusion. It was found that the theoretical valuesl coincided with the experimental valuesfor tangential thermal conductivity of thirty-six wood spicies and radial thermal conductivity of twenty-three, respectively. The methods that have been used to analyse the radial thermal conductivity are also suitable for the longitudinal thermal conductivity.

Key words: Air-dried wood, Thermal conductivity, Cell model of wood, Diffusion