Effects of High Temperature Heat Treatment at 185℃ on Physical Properties of Ash Wood

The effects of high temperature heat treatment at 185℃ in commercial scale on the physical properties( density,hygroscopicity,and dimensional stability) of ash wood( Fraxinus mandshurica) were determined and analyzed in this paper. The results showed that: the oven-dry and air-dry densities of heat treated ash wood was slightly less than that of the reference; the hygroscopicities of heat treated ash wood were obviously lower than the reference,meanwhile,the difference of EMC between heat treated and reference of ash wood increased with relative humidity; when the specimens were in equilibrium at two environments with temperature 60℃,relative humidity 40 %( dry condition),80 %( moist condition) respectively,swelling ratio in tangential and radial direction of heat treated ash wood were declined at different level,the ASE( anti-shrink efficiency) reached 55. 53 % and 47. 34 % in the above two environments,the dimensional stability of heat treated ash wood was improved remarkably.