Abstract
To follow the process of basal-bend formation in young sugi (Cryptomeria japonica D. DON), the author measured the amount of deviation from the vertical of stems at many points from the base to the top. Measurements were made before snowfall and after thawing, and then about every ten days until the beginning of November. The results were as follows: 1) The permanent basal-curve of a stem was not caused directly by snow pressure, but its formation depended upon the rate at which the lower stem recovered verticality after the pressure had been released. 2) A stem prostrated by snow pressure was inclined together with its root system; the stem suffered elastic strain along its entire length; elastic strain, elastic after-strain, and permanent deformation formed in the stem. 3) In early spring, after release from snow pressure, the stem began its straightening with rapid, simple elastic recovery; then elastic after-strain followed. 4) The stem complete its recovery through elastic after-strain until the end of April or early May at which time the stem resume its recovery with growth and the forming of compression wood. 5) Increase in weight with tree growth also contributed to basal-bend formation in 1- and 2-year-old trees.
