2014 Volume 22 Issue 2 Pages 57-67
Although exclusively used for hoes and spades since the Yayoi period, Quercus gilva is known only as fruits in storage pits before that, and it was unknown in what kind of forest or since when this species grew in western Japan. At the Tarumi-hyuga site on the northern shore of the Osaka bay, fossil woods and plant macrofossils of the initial and middle–final Jomon periods were obtained. These fossils showed that a deciduous forest of Aphananthe aspera, Zelkova serrata, and Carpinus tschonoskii existed before the fall of Kikai-Akahoya tephra (K-Ah) and that a lucidophyll forest of Quercus subgen. Cyclobalanopsis including Q. gilva and Cinnamomum camphora existed after the fall, agreeing with the pollen analyses carried out around the Osaka bay. From an extant lucidophyll forest in Miyazaki, the lucidophyll forest established after the fall of K-Ah differed in the dominance of canopy trees, but had a similar species composition, added with species growing in open disturbed areas, probably reflecting an unstable habitat at the foot of Mt. Rokko. Considering other records of plant macrofossils, lucidophyll forests with Q. gilva spread around the Seto sea around the early Jomon period after the fall of K-Ah.
