Abstract
We described the stratigraphy, wood fossil, plant macrofossil, and pollen fossil assemblages of the wood peat bed with buried stumps in the southern part of the Yogo lowland along the Yanagase fault, and reconstracted a vegetation in and around the lowland based on the plant fossil assemblages. The wood peat was deposited during the late Holocene from ca. 4500 to 3500 years ago, based on radiocarbon dating. It was suggested that the Alnus japonica-Fraxinus mandshurica var. japonica forest stood in the central part of lowland, and the forest vegetation composed of many coniferous and broadleaved species such as Cryptomeria, Aesculus, Carpinus tshonoskii, Cephalotaxus harringtonia, Quercus serrata, Castanopsis, and Quercus subgen. Cyclobalanopsis, distributed in the surrounding area. The finding of Fraxinus mandshurica var. japonica in the Y ogo lowland suggested cooler climate than at present and a formation of wood peat related to such climatic condition. An expansion of lake area occurred due to the activities of the Yanagase fault might led caused a disappearance of forest in the central part of lowland at ca. 3500 years ago.
