T. Sato’s scientific contributions

We analyzed the use of honey source plants in apiculture in Hokkaido, northern Japan, based on the "Annual Report of Honey Source Research" published by the Hokkaido Association of Apiculture. Black locust, basswood, clover, Amur corktree, thistle, buckwheat, and horse chestnut were reported as the seven primary honey source plants in Hokkaido. Tree species accounted for approximately 70% of the total honey production among the seven plants, and nearly 80% was explained by adding thistle, one of the forest understory plants. This indicates that forests play an important role as honey sources. Cluster analysis divided Hokkaido into five geographic regions based on the composition of honey source plants in each region (sub-prefecture): Pacific region, Okhotsk region, Northern Hokkaido, Central Hokkaido, and Southern Hokkaido. For basswood and Amur corktree in particular, tree biomass in each region was exponentially correlated with the number of beehives that targeted each tree species. Regional diversity in the seven primary honey source plants was also correlated with the cumulative number of beehives, implying that high productivity can be achieved by having a high diversity of honey source plants.