Effects of snow cover on seed survival and seedling distribution of beech: Protection from seed predation by rodents

Abstract

Beech trees often dominate the natural forests in northeast part of Japan. This is partly attributable to heavy snow environment in these districts. Deep snow cover during winter season may contribute to protect seeds on the ground from wood mice otherwise they totally feed or remove seeds. To verify this hypothesis, at sites around and far from stems of canopy trees, we compared snow disappearance date, seedling densities and seed removal rate by rodents. Snow cover around stems disappeared earlier than far sites. Correspondingly, seedlings were scarcely found around stems, while seedling banks established 2-3 m apart from mother stems. Moreover, seed predation rate by mice were higher around stems than sites far from stems. However, experimental addition of snow pack around stems depressed the predation rate significantly. These results suggest that snow cover prevents rodents from seed feeding and plays an important role for successful regeneration. This may also be one of the reasons why beech tree can establish at high density level in snowy regions.