Biome classification from Japanese pollen data: application to modern-day and Late Quaternary samples

Abstract

Thirty four arboreal pollen taxa were assigned to plant functional types and then classified to eight forest biomes in Japan and adjacent areas. When applied to 285 surface pollen spectra from Japan, the method assigns 78% (222 sites) of the samples to the correct biome. The method is particularly good at reconstructing warm-mixed, temperate deciduous, temperate conifer and cool-mixed forests, but the reconstruction of cool-conifer forest was difficult. The method has been applied to the late Quaternary pollen record from Lake Mikata, central Japan (35°33’22” N, 135°53’40” E, 0 m a.s.l.) to reconstruct vegetation changes since ca 40,000 yr BP. The reconstruction shows that temperate deciduous forest dominated around Lake Mikata before 25,000 yr BP. A phase of cool-mixed forest (now present only in Hokkaido, 1000 km to the northeast) is reconstructed between ca 22,000 and ca 18,000 yr BP, corresponding to the coldest stage of the Last Glaciation. This coldest phase is bound by two transition phases that are characterized by co-dominance of cool-mixed and temperate deciduous forest vegetation. The Holocene vegetation is represented by warm-mixed forest that grows around the site today.