Masting of Fagacea Trees critically decide the lifehistory of the Japanese Black Bear at Chichibu mountainous area.

　　Plant - animal interactions are the important factors in the evolution of both masting and animals' breeding strategies. Predator satiation and several other hypotheses explaining the origin of masting can be analyzed, and the examination of masting theories can be improved, by more observation of the interactions in the population level and also with genetic insights. The black bear can affect the beech trees' breeding strategy and maybe a factor in the natural selection of their masting phenotypes as a seed disperser.

Key Words: Masting, Predator Satiation, Plant-Animal Interaction, Asiatic Black Bear, Mouse, Fagacea