Abstract
To clarify the features of lower-story trees facing high risk of snow accretion damage in the two-storied forests, snow accretion damage was examined in a two-storied Cryptomeria japonica plantation (109-year-old for the upper-story trees and 19-year-old for the lower-story trees) in Iwate Prefecture. The range and average of the height/diameter ratio for the lower-story trees was 63-131, 94.7, respectively. The relative number of total damaged lower-story trees was 28.4%, among them fatally damaged ones (stem breakage and arch, etc) amounted to 21.2%. The height/diameter ratio significantly correlated with the occurrence of snow accretion damage, while the distance from the nearest crown edge of upper-story trees did not remarkably correlate with the damage. The result of present study is different from some previous studies emphasizing the effect of spatial relationship with upper-story crowns, suggesting that the damage outbreak mechanisms are various due to stand structure of two-storied forests such as openings among crowns and heights of the upper-story trees.
