Migration and development for Cryptomeria japonica since the last glacial period in western Japan

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Based on this study and previous palynological data (Takahara and Takeoka, 1992 ; Takahara et al., 1999), it is clear that Cryptomeria japonica had full-glacial refugia along the coastal corridor of the Sea of Japan, western Japan. The inference of C.japonica refugia (Tsukada, 1980 ; 1982 ; 1986) is confirmed by the evidence from Oki Islands of this study. Also, this study indicates that the population of C.japonica in the Palaeo-Oki Peninsula was larger than at other sites in western Japan. In the Wakasa Bay area, which is also regarded as a C.japonica refugia, the species increased abruptly in the early Holocene, and then spread throughout the Holocene (Yasuda, 1982 ; Takahara and Takeoka, 1992 ; Takahara et al., 1999). On the other hand, around Lake Shinji, which is located south of Oki Islands on the Sea of Japan coast near the middle of the Chugoku region, development of C.japonica during the early Holocene is not evident (Onishi, 1977), probably because southward migration of C.japonica from the Palaeo-Oki Peninsula into the present coastal area of the middle Chugoku region was prevented by a rapid rise in sea-levels in the late-glacialyptomeria japonica pollen percentages at 18000, 11000, 8000, 6000, 4000 and 2000 yr BP in western Japan were compiled on longitude-latitude and longitude-altitude diagrams. These diagrams shows migration and development for Cryptomrtia japonica from the last glacial maximum to the late Holocene.