Late-quaternary shift offagus distribution

Abstract

Based on six resolved maps of its pollen frequency (dating 13,000, 10,000, 8,000, 6,000, 3,000 and 500 yr B.P.) at 33 sites scattered almost throughout the Japanese Archipelago,Fagus shows principally a, unidirectional late-Quaternary shift in distribution from the southwest to the northeast. The maximum areal coverage was from 10,000 to 7,000 years ago, although northeastern populations were not fully developed by this time. The northern limit ofF. crenata, which has virtually not changed in the past 7,000 years, was probably regulated by total precipitation during the growing season from April to October (called the effective precipitation). ForF. crenata to migrate farther north in Hokkaido under the modern temperature regime, a minimum of 800 mm of precipitation, evenly distributed over this period, is required.