Altitudinal variation in freezing resistance of Saghalien fir (Abies sachalinensis)

Abstract

Altitudinal variation in freezing resistance of Abies sachalinensis in central mountainous areas in Hokkaido was investigated. Freezing resistance of winter buds of the open-pollinated progenies from 51 mother trees and ramets from 80 clones, growing at different altitudes, was assessed. Freezing resistance increased with increasing altitude from about 300 to 1200 m. The increase in freezing resistance was always accompanied by a decrease in the variance. These results suggest that natural selection has operated under influence of winter temperature gradients to bring about the hardiness related to altitudinal occurrence.