Vegetation history during the last 28,000 years in Tamba Highland, Kyoto, Japan based on multi-analyses of sediment from the Jaga-ike mire

要旨

Sediment cores obtained from the Jaga-ike mire, located in the inland mountainous area of the Kinki region in western Japan, date back to 28,000 cal BP. The vegetation history around the Jaga-ike mire since the Last Glacial period was reconstructed using multiproxy analyses (pollen, macrofossils, and charcoal). From 28,000 to 20,000 cal BP, forests were dominated by pinaceous conifers such as Abies, Tsuga, Picea , and Pinus as well as Betula trees. The genus Picea included Picea jezoensis var. hondoensis based on macrofossil analysis. Pinaceous conifer forests were most developed between 26,000 and 20,000 cal BP. Between 20,000 and 15,000 cal BP, the population of deciduous broad-leaved trees gradually increased. During the Late Glacial period, from 15,000 to 12,000 cal BP, broad-leaved forests mainly comprising Fagus crenata , deciduous Quercus, and Carpinus/Ostrya species developed. Between 10,000 and 7,000 cal BP, forests dominated by Castanea crenata expanded likely in response to frequent fire events. During this period, the forests included Carpinus, Fagus japonica, Q. subgen. Lepidobalanus, and Cryptomeria japonica . Immediately after 7,000 cal BP, Quercus dentata, which is tolerant to fire, temporarily increased in deciduous forests in relation to severe fire events. Between 7,000 and 6,000 cal BP, Cryptomeria japonica mixed with deciduous broad-leaved trees such as Carpinus/Ostrya and Q . subgen. Lepidobalanus . After 6,000 cal BP, C. japonica formed forests together with cool temperate deciduous broad-leaved forests such as F. crenata and warm temperate evergreen broad-leaved forests mainly composed of evergreen Quercus formed adjacent to them. The vegetation records at the Jaga-ike mire show intermediate characteristics between the development of C. japonica on the Sea of Japan side caused by the Tsushima Warm Current and the development of evergreen broad-leaved forests on the Pacific side influenced by the Kuroshio Warm Current.

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