Relationship between Wood Anatomical Properties and Specific Permeability of Sugi (Cryptomeria japonica) Sapwood and Intermediate Wood

The objective of this study was to clarify anatomical factors which determine specific permeability of sapwood and intermediate wood in air-dried sugi (Cr?~ptomeria juponica) wood. Superficial air permeability of sugi sapwood and intermediate wood was measured and then specific permeability was determined. Using these specimens for permeability tests, the proportion of latewood and earlywood, the percentage ol aspirated and incompletely aspirated pits, the number of bordered pits per tracheid, the number of tracheids per unit area and tracheid length were obtained. Specific permeability decreased with increasing levels in the stcm except for the lowest level and also related to distance from pith, suggesting that cambial age is related to specific permeability. A clear relationship between percentage ol latewood and specific permeability was not found, suggesting that effective pathways in earlywood determines permeability. Specific permeability of intermediate wood and sapwood were significantly related to the number of effective open pits in earlywood, Mi3J, which was determined by anatomical properties such as aspirated and incompletely aspirated pits, the number of pits and tracheids, and proportion of latewood, suggesting that specilic permeability of sugi sapwood and intermediate wood is a physical value determined by the intrinsic properties of earlywood in addition to the condition of bordercd pits.