RECOVERY OF A SASA-TSUBOIANA POPULATION AFTER MASS FLOWERING AND DEATH

The recovery process of a Sasa tsuboiana population after a mass flowe ring and death in 1977 was investigated by 15 years of observation in the Hira Mountains, Kinki district, western Japan. Seed production was high (6600-13 800 seeds m-2 in Sasa plots and 3900 seeds m-2 in a for est plot) but emergent seedling density was low (14-21 seedlings m-2), probably because of seed predation by Microtus montebelli occurring b etween seed shedding and the next spring. The seedling density had dec reased further by the next year and the S. tsuboiana population recove red from only a limited number of seedlings. In spite of such a low in itial density, the S. tsuboiana population was able to regenerate succ essfully and attained the previous full stand height in 7-16 years. Mi scanthus sinensis invaded and delayed the recovery of S. tsuboiana in one plot, but S. tsuboiana became dominant as it caught up with the he ight of M. sinensis. Seedling growth patterns, such as frequent tiller ing, the onset of rhizome extension in the early stage of seedling gro wth and frequent culm production from rhizomes, played important roles in the successful regeneration of S. tsuboiana.