Development and distribution of Castanea and Aesculus culture during the Jomon Period in Japan

Castanea and Aesculus trees were protected for consumption of nuts as food during the Jomon Period. Climatic factors affected the selection of kinds of consumed nuts. Castanea was mainly consumed during warm periods and Aesculus was consumed during cold periods. However, this could have been a regional phenomenon in northern Japan. It is possible that in southern warmer areas Castanea either might be protected constantly, or the protection of these plants was not necessary because forest productivity in the southern area is greater than that of the northern area. To understand the influence of temperature on Castanea hansaibai, pollen analysis was conducted at the Satohama site. In addition, the distribution of the intermediate stage between wild and domestication (hansaibai) during the Jomon Period was studied based on pollen analyses.At the Satohama site, protection of Castanea started during the warm period in the Early Jomon Period (7000–4500 years BP) and continued to be observed during the next cold period. The Tohoku region (the northern part of Honshu Island) and the Hokuriku region (Japan Sea Coast area in Central Japan) was the main distribution area. In this study, no evidence of the protection of either species in Western Japan was detected. Climate and the necessity for large amounts of food preservation for winter might influence this activity.