2016 Volume 33 Issue 1 Pages 33-43
Japanese temperate conifers, Picea sect. Picea and Pinus koraiensis, are rare at present in Japan. Previous palaeobotanical studies report on macrofossil data for those conifers obtained throughout Japan at the Last Glacial. These results suggest that those conifers have experienced unique distribution history since the Last Glacial. We surveyed the distribution of a Picea koraiensis （Picea sect. Picea）-Pinus koraiensis-deciduous-broadleaved mixed forest along a soil moisture gradient in the upper stream of the River Ussuri in the Russian Far East, to reconstruct the reliable distribution history of the Japanese Picea sect. Picea and Pinus koraiensis. The two conifers are principally distributed on the mesic and moist sites with deciduous broad leaved trees such as Acer mono, Tilia amurensis, Fraxinus mandshurica and Ulmus japonica. They appear with a few amount on the dry sites, where xeric species such as Quercus mongolica, Betula davurica prevail. The survey results show that 1） the Japanese Picea sect. Picea and Pinus koraiensis are ecologically temperate mesic - moist type in nature, 2） actually no continental type of coniferous forests consisting of the two species occurs in the Russian Far East as well as in central Japan at present. The most prominent feature of the tree distribution at the Last Glacial in central Japan was that the Japanese Picea sect. Picea and Pinus koraiensis made the mixed forest with deciduous broadleaved trees in the lowland and hilly areas on mesic and moist sites. The abundant outcrops of macrofossils of the Picea sect. Picea and Pinus koraiensis in the Last Glacial throughout Japan indicate that at the Last Glacial they prevailed on the mesic and moist sites which preserved macrofossils well.
