Abstract
Forests buried by latest Pleistocene tephra layers from Asama volcano were studied in the Minami-Karuizawa basin, Nagano Prefecture. A number of tephra layers were deposited since ca. 25,000 yBP in the Minami-Karuizawa basin, and peat, peaty sediments, and soil were deposited between them. Buried forests were found from below Asama-Kumoba pumice flow deposit (As-Kb) to above an unnamed tephra layer (MK-15) and were especially extensive below Asama-Itahana yellow pumice (As-YP) dated at 13,320±130 to 13,710 ± 130 yBP. Buried forests below As-YP were dominated by Picea and Pinus cf. pumila, accompanied by Juniperus, and were more developed on herbaceous peat than on moss peat. At localities or horizons where Picea and Pinus cf. pumila were not dominant, Picea, Abies, and Larix dominated. In the Minami-Karuizawa basin, coniferous forests similar to the present subalpine ones seem to have grown in drier areas, whereas open Picea sect. Picea–Pinus pumila forests seem to have grown in wetter areas. Contemporaneous fossil wood assemblages buried by As-YP in the Maebashi area was dominated by Picea, accompanied by Larix and Pinus subgen. Haploxylon, and coniferous forests seem to have had an extensive distribution at this period.
