Abstract
Cryptomeria japonica is considered to be the primary component of Japanese vegetation history, evidenced by pollen analytical data for the period since the Last Interglacial Epoch. The other main components include some Pinaceae and deciduous oak, although beech forest and evergreen-leaved forest were not distributed in a wide area, when compared with the Post-Glacial Period. This information differs from the supposed vegetation during wide climatic movement based on a temperature change. Therefore it is necessary to recognize the regional different forest under the same climate. From pollen analyses on the Pacific Ocean side of the Tohoku district, the deciduous broad-leaved forest, including beech, was distributed across a wide area until 4000 yr. B.P., at which time fir trees as well as evergreen oaks increased in the southern part of the district up to 3000 yr. B.P. Although the distribution of beech forest shrank during that period, it expanded again until 1000 yr. B.P. After that time, the recent forest vegetation was consisted of evergreen and deciduous oak in the southern part, while mixed deciduous beech forest accompanied by Fagus japonica around the northern part. These various changes might be caused by a climatic change and human impact.
