The resistance of sugi (Cryptomeria japonica) to basal bending

Abstract

To clarify the factors playing an important role in basal bending, sugi (Cryptomeria japonica D. DON) stem forms under snow were surveyed. Snow pressure damage was classified after the snow melted, and the degree of resistance of the roots; weight of stems, branches, and leaves; length; angle and number of branches; and the modulus of elasticity in bending also were measured. The cultivars having a large degree of basal bending mainly were leaning under the snow, but there was little stem breakage. Cultivars with a small degree of basal bending were less frequent with stems leaning under the snow, but much breakage was observed. According to analysis of multiple regression by using the amount of stem deviation from the vertical, the modulus of elasticity in bending, the angle of branches and the length of branches play an important role in the prevention of basal bending. In particular, the modulus of elasticity has a confirmed negative relationship with the basal bending.