• Wang, Song-Yung
  Dept. of Forestry, College of Agriculture, National Taiwan University, Taipei
  
• Chiu, Chih-Ming
  Taiwan Forestry Research Institute, Taipei, Taiwan, ROC
  

The variations of cell-wall crystallinity of seeding and cutting originated Japanese cedar (Cryptomeria japonica D. Don) growing under various thinning intensities in Taiwan were investigated.

The degree of crystallinity increases from the pith outwards toward the bark, and then it levels off to a constant value at the 15th annual ring. The degree of crystallinity is smallest at the trunk base near the pith; the largest mean value is located at 20% to 40% of the total tree height, whereas the smallest mean value is at the apex. The degrees of crystallinity measured by the peak height method (CrI) and by the area method (KI) range 50-70% and 40-60%, respectively.

The degree of crystallinity of the seeding-originated tree seemed to be smaller than that of the cutting-originated tree, but their difference was not significant by the F value test. In addition, the wood from the heavy thinning (C-thinning) had the smallest degree of crystallinity, but there were no significant differences among the other thinning intensities affecting the degrees of crystallinity.

The CrI values of mature wood ranged from 61.5% to 64.6% whereas the KI values were 52.9% to 55.6%. In the juvenile wood regions, the CrI values were 56.7% to 58.8%, and the KI values were 47.5% to 50.5%.