AbstractMoisture adsorption and hygroexpansion behaviors of southern pine (Pinus spp.) treated with 0.5, 1, and 2% concentrations of paraffin wax emulsion were investigated. The specimens, 4 mm along the grain and 20 mm in radial and tangential directions, were exposed to seven different relative humidity conditions of 11, 22, 33, 45, 60, 75, and 92% for adsorption at 30 °C, which was controlled by a self-designed temperature conditioning chamber. Weights and transverse dimensions of the specimens were measured at certain time intervals during the adsorption processes. Results showed that paraffin wax emulsion treatments could reduce both equilibrium moisture content and adsorption rate. Additionally, paraffin wax emulsion treatments also improved dimensional stability, as indicated by estimation of the humidity expansion coefficient (Y) as well as moisture expansion coefficient (X).