Wood peat found at some excavations in the alluvial plains of central Japan were deposited mostly during the Middle Jomon to the Latest Jamon Ages, 4,500~2,500 y. B. P. They are characterized by a high water content, a low degree of stratification, a heterogeneous composition of wood or wood fragments, and a low mineral content. The wood peat consists of macroscopic remains such as roots, stumps, trunks, branches, seeds and fruits of trees, and contain many pollen grains of their dominant or abundant taxa. Palaeobotanical studies of wood peat revealed that the vegetation consisted of fen wood or fen carr communities such as Alnus- Fraxinus forest with some herbaceous plants, and were formed under the mesotrophic to eutrophic nutrient status at or above the water table.
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