Archaeological remains of the Jomon period showing utilization of plant resources such as wooden structures for water usage and mounds of Juglans or Aesculus fruits were excavated at the Shimo-yakebe site in the Kanto plain. We revealed chronology of these remains by radiocarbon dating and examined changes in the utilization of plant resources, particularly food resources. Radiocarbon dating showed that these remains were made during ca. 5300–2800 cal BP of the middle to latest Jomon periods, concenctrated in five chronological groups. Groups S-1 (ca. 5300–4800 cal BP) and S-2 (ca. 4800–4400 cal BP) corresponding to the middle Jomon period were characterized by the utilization of Juglans fruits. Aesculus turbinata fruits were already used in group S-2. Groups S-3 and S-4 (ca. 4500–3300 cal BP) showed not only prominent utilization of Aesculus turbinate fruits, but usage of various resources such as Quercus subgen. Cyclobalanopsis and Quercus sect. Aegilops fruits. Castanea crenata was continuously utilized until group S-5 (ca. 3400–2800 cal BP) of the latest Jomon period. The utilization of food resources at the Shimo-yakebe site was more multi-layered than the previously proposed simple transition from Castanea in the middle Jomon period to Aesculus in the late and latest Jomon periods.

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Use of timber resources in the late to latest Jomon periods at the Shimo-yakebe site, Tokyo, was studied based on a refined chronology from detailed 14C dating by AMS. Through the periods, Castanea crenata was used preferentially for large constructions in the lowland, and other deciduous trees were employed together with Castanea crenata for smaller constructions. Comparison of the timber usage at the Shimo-yakebe site with that at three contemporaneous sites in the Kanto plain showed that Castanea crenata accounted for 50–80% of timber used for large constructions, but were used with other trees in smaller constructions. These trends seemed to show that timber was obtained mainly from artificial forests of Castanea crenata around dwelling areas for important constructions, but from a restricted area of these Castanea forests and the surrounding forests for smaller constructions. The diameter of trees used for constructions ranged more widely for larger constructions, but averaged at about 10 cm for all constructions, indicating their extraction from similar forests. At these sites, the wide ranges in the diameter and the number of growth rings among Castanea crenata trees showed that these trees were brought not from uniform forests, but from heterogeneous ones around the dwelling areas.

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Utilization of plant resources was reconstructed from plant macrofossils found in and around the lowland structures at the Shimo-yakebe site, Tokyo. Lowland structures and plant remains were dated from the middle phase of the middle Jomon period to the middle phase of the latest Jomon period. In the middle phase of the middle Jomon period, Juglans mandshurica middens were found with fruits of Quercus aliena and Castanea crenata. Seeds of Aesculus turbinata came to be used in the late phase of the middle Jomon period. In the late Jomon period, use of Aesculus turbinata seeds became prominent. In this period, several lowland structures were constructed and a lot of baskets were accompanied with acorns of Quercus sect. Aegilops and Q. subgen. Cyclobalanopsis. In the latest Jomon period, the remains of Quercus aliena increased once again, with the continued use of Castanea crenata. Beside acorns and nuts, domesticated plants such as Lagenaria siceraria and Cannabis sativa, bulbs similar to those Allium, and fruits of Sambucus racemosa subsp. sieboldiana and Morus australis were also used through these periods. Thus, Jomon people used various plants in the latter half of the Jomon period, and their usage became more multi-layered with the utilization of lowland environment in the late Jomon period.

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We identified polypores excavated from the Shimo-yakebe site, Higashi-murayama city, Tokyo. We found Ganoderma applanatum, Daedalea dickinsii, and Abundisporus pubertatis from horizons of the Jomon period and only G. applanatum from horizons of the Kofun or later periods. Based on the ecology of each species and the size of individuals, we tried to clarigy forest vegetation around the site.

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Field research of the paleoforest buried by a pyroclastic flow from the gigantic eruption during the third to fifth centuries, El Salvador, Central America is reported.

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[in Japanese]

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