Impact of a strong typhoon on the structure and dynamics of an old-growth beech (<Emphasis Type="Italic">Fagus crenata</Emphasis>) forest,southwestern Japan

Typhoon no. 19 of 1991 (T9119) caused multiple treefalls and created large openings in an old-growth beech (Fagus crenata) forest at Mt. Daisen, in the Daisen Forest Reserve, southwestern Japan. The area of the largest opening was about 1.7 ha (300 m by 70 m). To predict the dynamics of the beech stand after the disturbance of T9119, we investigated the damage to the stand and the density and growth rate of trees with DBH=5–10 cm in a 1-ha plot covering a large part of the largest opening and the adjacent closed canopy. The beech did not regenerate immediately. The regeneration and growth rate of trees with DBH=5–10 cm were related to the frequency of the typhoon attack for at least the past century. In beech forests, small gap formation is the prevailing mode of disturbance. Our results indicate that typhoons affect the structure and dynamics of this beech stand. We suggest that both small gap formation and large-scale disturbance are important for the maintenance of beech forest in some areas.