Reconstruction of the forest vegetation around the Kanto plain during the late Glacial and the Holocene

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The aim of the present research is to reconstruct the forest vegetation during the late Glacial and the Holocene around the Kanto plain where the present climax forest vegetation is thought to be evergreen broad-leaved forest. The excavation of a early Jomon remain in Chiba Prefecture, a marginal of the Kanto plain, which is very rare in Japan, revealed that even at the late Jomon period the forest vegetation consisted of the elements of the deciduous broad-leaved trees such as Phellodendron, Ostyria and Actinidia.. This finding suggested that the human activity during the Jomon period kept the continental type of the deciduous broad-leaved forests among the evergreen broad-leaved forests which expanded at the Holocene. The vegetation distribution in the early Jomon period was reconstructed in a small valley head at the Chiba prefecture to clarify the development process of the forests around the Kanto plane during the Holocene. On the bottom of the valley distributed the Alnus forests, while on the slopes and the terrace occupied the Quercus serrata forests. The vegetation history of the Kanto plain during the late Glacial and the Holocene was assumed to be as follows : At the full Glacial, the continental type of the deciduous broad-leaved forests prevailed around the Kanto plane consisting of Carpinus, Quercus serrata, Castanea crenata, Acer etc. In the early Holocene, the period human activity started, evergreen broad-leaved forests expanded. However the human activity prevented a full expansion of the evergreen broad-leaved forests, keeping continental type of the deciduous broad-leaved forests among the evergreen broad-leaved forests. Thus the present secondary deciduous broad-leaved forests around the Kanto plain derived from the continental type of the deciduous broad-leaved forests at the full Glacial, suggesting this forest is a historically important issue which should be preserved carefully.