<Original>Studies on the Improvement of the Pinning Method for Marking Xylem Growth I. : Minute Examination of Pin Marks in Taeda Pine and other Species

Abstract

In order to make an accurate estimation of the location of cambium at the time of pin insertion, pin marks left in the xylem tissue were minutely examined. The size and shape of the abnormal tissue induced by pin insertion depended on the size of needle, growth rate of trees, and the tree species. Since the abnormal tissue changed its shape and size as the cross section receded from the center, it was concluded to be necessary to use the cross section obtained from the center of pinning for correct application of the pinning method. The site relation between cambial initials at the time of pinning and the abnormal tissue was investigated following the modified Wolter's procedure. As a result, the site of cambial initials at the time of pinning was assumed to be at the cambial-side margin of the spindle-like abnormal tissue.