The Pinus pumila zone during the Last Glacial Age in Japan reconstructed from present growth and distribution of Pinus pumila

Abstract

The presence or absence of the Pinus pumila zone during the Last Glacial Age in Japan is discussed on the basis of the present distribution and growth of P. pumila, on the assumption that summer temperature declined and winter precipitation decreased. At present the height, coverage, mean annual stem elongation and production rate of P. pumila scrub correlate with each other. Expansion and reduction of P. pumila scrub in the Last Glacial Age can be inferred from those relationships. Mean annual stem elongation and production rate decreased with the reduction of summer temperature. Scrub height decreased with the decrease of snow depth around the stands. These facts suggest that the distribution of P. pumila scrub will be reduced when summer temperature declines and winter precipitation decreases. From this, it can be deduced that in the Last Glacial Age the distribution of P. pumila scrub is supposed to have strongly shrunk in the uppermost part of the mountains where the P. pumila zone is located at present; the P. pumila zone probably disappeared there. -from English summary