Abstract
Many roots of Chamaecyparis pisifera were dug out of the ground at the southern part of Inawashiro basin, Fukushima prefecture (Fig. 1) in 1985. The author got an information that they had lived on the shore plain of Lake Inawashiro when the lake level was lower than present about 2m. Then they had been buried after the change of the environment such as a rise of the lake level and accumulation of alluvial deposits.
The radiocarbon dates of them were between 1, 800y BP and 1, 900y BP (Table 1). The result of dating and the deduced geomorphic environment suggest that the paleo-lake level of Lake Inawashiro at about 1, 900y BP was about 2 meters lower than present (514m).
