抄録
The author drew the map of primeval vegetation in lowland of Hokkaido (Fig. 1), and compared it to the present distribution of rice-crop per tan (_??_10a.). The distribution of Mores Bombycis and Juglans Sieboldiana, is especially well correlates to that of Oryza sativa. The coefficient of mean square contingency between regions of vegetation and rice-crop C1=0.66. C2, while such between mean temperature in August and rice-crop is 0.71. Although the datum is rough and raw, the correlation it high, hand utilization in Northen part of Japan will effectively depend upon the study of vegetation indicator.
