日本に自生している針葉樹の耐凍度とそれらの分布との関係 FREEZING RESISTANCE OF CONIFERS IN JAPAN WITH SPECIAL REFERENCE TO THEIR DISTRIBUTIONS
Dormant one-year-old twigs were collected from the mature and young plants of a number of conifer species cultivated at Yamabe, Hokkaido, and other places during midwinter, these were artificially hardened at sub-freezing temperatures to overcome differences in site of collection and to induce maximum freezing resistance. In most of the species distributed in the sub-alpine and sub-cold zones, the leaves and the twigs resisted freezing to -70℃ or below, while most of the species distributed in the temperate zone resisted freezing to only about -30℃, and the leaves and the twigs were found to be nearly equally hardy unlike the conifers distributed in sub-alpine and sub-cold zones. Also, most of these temperate conifers were observed not to be grown in a severe cold climate in Hokkaido. Thus, in the conifers distributed in the temperate zone, winter minimal temperatures appear to be the principal factor governing their growth in severe cold climates. A marked variation in hardiness was not observed among the pines Pinus denslflora and Pinus thunbergiana from different provenances.
日本生態学会誌 25(4), 192-200, 1975