We studied soil-genesis since the early Jomon period at the Sannai-maruyama site based on the relationship among soil-facies, vegetation, and human activity. In the early Holocene, the brown forest soils formed under deciduous broad-leaved forests, associated with dwarf bamboo, Sasa. Before the appearance of the village, ca. 5050 yr BP, the middle stage of the early Jomon period, the formation of the kuroboku soils (black colored humus layer) started. This occurrence synchronized with the expansion of the semi-grassland caused by the human forest clearance. Although the disturbance of soil layers owing to increasing human activities occurred in the maximum stage of the village during the middle Jomon period, the kuroboku soils have continuously formed under the artificial ecosystem of “human activities → forest clearance → expansion of semi-grassland”. Therefore, the kuroboku soils at the Sannai-maruyama site could be promoted by human activities.
The vegetation and environment in the middle Pleistocene in and around Hata, Takashima City, Shiga Prefecture, central Japan were reconstructed based on a plant macrofossil assemblage from the Hata Formation, Kobiwako Group. This assemblage composed mainly of fossil fruits and seeds included 20 genera and 17 families of 23 deciduous broad-leaf tree taxa, and 18 genera and 16 families of 27 herbaceous taxa. Conifers and evergreen broad-leaf trees were absent, and Alnus japonica, the most dominant taxon, amounted to 36.7 % of the total. Other major components were Styrax sp., Rubus, Mosla dianthera, and Carex including sections Carex and Praecoces. Cyclocarya, the only extinct taxon from Japan among the total 50 taxa, occurred from the uppermost horizon in the Kobiwako Group so far reported. The sedimentary facies of the peaty silt including the fossil assemblage was without any ripples or lamina and indicated sedimentation of a relatively autochthonous assemblage in a stagnant water in the backmarsh of a river. Thus, aquatic vegetation of Trapa and wetland forests of Alnus must have occupied the backmarsh, surrounded by mesic deciduous broad-leaved forests.
We analyzed 1934 wooden remains used in 17 storehouses, 23 cellars, 86 drains, and 5 wells at the Nihonbashi 1-chome site, Tokyo, and discussed the transition in construction timber usage in townspeople’s buildings of Edo during the early modern Edo period. Before the mid 17th century, various softwood and hardwood were used for drains and cellars, probably derived from local timber production and trade system to answer the urbanization and increased demand in Edo. After the mid 17th century, various softwood including Pinus densiflora were used for drains, and Thujopsis dolabrata was used for cellars. For storehouses that increased in the 18th century, Pinus densiflora, Castanea crenata, Cryptomeria japonica, and Tsuga were used for their foundations, and recycled timber was used for their support, reflecting establishment of timber industry and trade system allowing proper selection of materials for the main frames and that of a timber recycle system. Since the late 18th century, use of Cupressaceae decreased, and Pinus densiflora, Cryptomeria japonica, and Larix came to be used, reflecting extensive plantation of these trees. Throughout the Edo period, population increase and large fires such as the Meireki fire had a great impact on such transition in construction timber usage.