[M-IS12] 山の科学

[MIS12-09] 長野県志賀高原田ノ原湿原の花粉分析データからみた最終氷期末期以降における亜高山帯針葉樹林の発達過程

★招待講演

*吉田 明弘¹、佐々木 明彦² (1.鹿児島大学、2.国士舘大学)

キーワード：亜高山帯針葉樹林、花粉分析、田ノ原湿原、中部日本

To advance our understanding of vegetation history in the subalpine zone, we reconstructed vegetation changes at the Shiga Highland since the last deglaciation based on the well-dated pollen record from the Tanohara peat bog (1,660 m a.s.l.). The data from the site indicated 1) deciduous shrubland mainly Betula ermanii and Quercus crispula var. horikawae covered the area around the site in ca. 15.0~4.7 ka cal BP, 2) the expansion of coniferous trees such as Picea jezoensis var. hondoensis and Tsuga diversifolia started from ca. 4.7 ka cal BP, 3) Abies mariesii started to increase gradually after ca 3.0 ka cal BP. The timing of expansion onset among the coniferous trees would suggest a difference in their habitat. That is, P. jezoensis var. hondoensis can grow in harsh terrains such as talus cones or wet environments, and was likely the first species to populate the subalpine zone. In contrast, A. mariesii is deep-rooted and prefers moist soil, and likely started its expansion under the suitable conditions established by other coniferous trees.