14 巻 (1997) 1 号 p. 25-35
Owase District in Mie Prefecture, located on the south-east side of Kii Peninsula, is one of the wettest region in Japan. Annual precipitation in Owase city is more than 4,000 mm, and warmth index is 128.7℃・Month. Consequently, laurel forests have been able to develop on lowland and mountain slopes. Firstly, a phytosociological study was made of the laurel forests, which were classified into six community types : A, B, C, D, E and F. Pittosporum tobira community (A) is located on the seashore. Quercus phillyraeoides -Pittosporum tobira community (B) is on windy, steep slope, near the seashore. Quercus phillyraeoides - Dicarnopteris dicotoma community (C) is on sites with conditions similar to those of community (B). Castanopsis cuspidata var. sieboldii - Symplocos glauca community (D) and Castanopsis cuspidata - Photinia glabra community (E) are located from the seashore to lower elevations of mountainsides (<400m). On higher mountainsides (about 400〜700m) Quercus salicina - Cleyera japonica community (F) is found. Secondly, I investigated the relatioship between the six community types and site conditions. Owase District is a very wet region, but there are dry sites on the mountainsides where communities A, B and C are found. On less xeric sites, Communities D and E are distributed. On the basis of these results, the relationship between environmental gradient and community structure (complex sinusia) is discussed.