Abstract:The effect of bacteria on the gas permeability of the air-dired sapwood and heartwood of refractory spruce (Picea, jezoensis var. komarovii) was investigated by pretreatment-ponding. The axial gas permeability of wood samples was measured with rising-water volume-displacement method. The results showed that a ponding period of 10 weeks in stagnant water not only notably improved the permeability of sapwood, but also increased the petmeability of heartwood, whereas the permeability of heartwood samples was not improved uniformly. Only 50 percent of heartwood samples was increased after ponding. The increase in permeability of sapwood and a part of heartwood were probably due to the attack of bacteria such as Bacillus brevis etc. Scanning electron microscopy suggested that tori in most of the bordered pits in sapwood tracheids were degraded, with the presence or the bacteria in the vicinity of the bordered pits in heartwood.