Abstract
Progress of the Cryptomeria japonica pollen front in 2018 (Fig. 1) was monitored by
tracking the first day of pollen release using a Durham sampler at 83 sites and an IS-Rotary sampler at 8 sites distributed from Hokkaido to Kyushu.
Results from the Durham sampler showed that, in early February, the pollen front had reached northwestern Kyushu and southern Kanto and Tokai. In mid-February, the front reached southern and central Kanto, southern Tokai and Kinki, western Chugoku, and almost all of Kyushu and Shikoku. In late February, the front had moved up to northern
Kanto, central Chubu, central and northern Kinki, and eastern Chugoku. By early March, the front was observed in central Tohoku, Hokuriku, and unexpectedly, southern Tokai and northern Chugoku. In mid-March it reached northern Tohoku. The front finally arrived in eastern Hokkaido in late March to early April.
