スギ材の気体透過性

生材丸太における心材・白線帯・辺材の気体透過性

抄録

To compare and investigate the air permeability in heartwood, white zone wood and sapwood in green logs of Cryptomeria japonica, each of the points in the log specimen set in vacuum chamber was connected to mercury manometer, and the changes of pressures in those were measured in the stages of vacuuming. The several experiments were carried out at the different log conditions, i.e. the conditions of opening or sealing of transverse section, radial section and log surface were changed, and the air permeability of longitudinal, tangential and radial directions were investigated with respect to each of the points.
The results obtained were as follows.
1) The air permeability in white zone wood was remarkably high, in comparison with those in heartwood and sapwood.
2) In heartwood, the air permeation was scarcely detected for all of three directions whether the moisture content was high or low.
3) In white zone wood, the air permeability was high for both of longitudinal and tangential directions, and that of longitudinal direction was higher than that of tangential direction.
4) In sapwood, the air permeability of tangential direction was obviously higher than that of radial direction.
5) The air permeability in each of the points were graded on the basis of opening or not of radial section for slitting by saw, i.e. white zone wood (there is opening of radial section for slitting)≥white zone wood (there is not opening of radial section)>sapwood (opening)>>sapwood (not opening)>>heartwood (both).