Orbital-scale vegetation variability during MIS 6， 5,4， and 3 based on a pollen record from the Takashima-oki core in Lake Biwa, western Japan

摘要

The pollen record from the Takashima-oki core in Lake Biwa provides information on orbital-scale vegetation variability during MIS 6, 5, 4， and 3. Pinaceous conifers, such as Picea and Tsuga, became dominant around Lake Biwa in MIS 6. In the first half of the last interglacial, deciduous broad-leaved forests composed mainly of deciduous oaks and beech developed, whereas the development of evergreen forests was limited by cold winter due to low winter insolation. In the second half of this period, under a moderate winter climate, due to increasing winter insolation, evergreen oaks increased. Lagerstroemia trees were present throughout the entirety of the last interglacial period. Temperate conifers, such as Cryptomeria japonica, Sciadopitys verticillata, and Cupressaceae trees, were dominant during MIS 5. Cryptomeria japonica then became dominant, especially during the second half of MIS 5e, MIS 5c, and MIS 5a. During MIS 4, pinaceous conifers, such as Pinus subgenus Haploxylon, Tsuga, and Picea, increased again. Mixed forests composed of deciduous broad-leaved trees, temperate conifers, and pinaceous conifers expanded during MIS 3.