Vegetation history since the last glacial period in the Mikata lowland, the Sea of Japan area, western Japan

Abstract

AbstractLocal and regional vegetation since the last glacial period was reconstructed on the basis of a palynological study of sediment at Iwaya, in the Sea of Japan area, western Japan. During the interstade (before about 30 000 years BP), forests were composed predominantly of Cryptomeria japonica with Tsuga sieboldii and cool‐temperate deciduous broad‐leaved trees. In the pre‐full‐glacial, the full‐glacial and the early late‐glacial (30 000‐12 000 years BP), forests were dominated by temperate (montane) and boreal (subalpine) Pinaceae and Betula. During the early full‐glacial, the pinaceous forests were mixed with cool‐temperate trees such as Fagus crenata. In the late full‐glacial (18 000‐16 000 years BP), the maximum development of pinaceous conifer forests was recognized. Cool‐temperate broad‐leaved forests composed mainly of F. crenata and Quercus (Lepidobalanus) replaced the pinaceous forests at about 12 000 years BP and were maintained to the early postglacial. Cryptomeria japonica was distributed around the Mikata lowland during the last glacial. Cryptomeria japonica, which began to increase at 16 000 years BP, increased abruptly in the early postglacial and spread throughout the postglacial in the lowlands. After 6300 years BP, lucidophyllous forests composed mainly of Quercus (Cyclobalanopsis) and Castanopsis were established in the Mikata district; this was later than in the inland and the Pacific Ocean areas in the Kinki region, western Japan. In historic times (after ca 2000 years BP), secondary forest of Pinus densiflora, which can grow as a pioneer in disturbed habitats, spread.