Abstract
The progress of the Cryptomeria japonica pollen front in 2012 was monitored by tracking the first day of pollen release from Kyushu to Hokkaido using a Durham sampler at 98 sites, and an IS-Rotary sampler at eight sites. Results from the Durham sampler showed that, in mid February, the pollen front had reached southern parts of the Boso Peninsula, Tokai, Kii Peninsula, and western parts of Kyushu. In late in February the front had moved up to the southern part of Kanto, Tokai, almost the whole of Shikoku, the western part of Chugoku and most of Kyushu with the exception of its western areas. Early in March the front was observed in wider areas from the central to the western part of Honshu: i.e. the northern parts of Kanto, Chubu and Kinki, and almost the whole of Chugoku. By mid March, it had reached the southern to central areas of Tohoku and, by late March, it reached northern Tohoku. The front finally arrived in the southern part of Hokkaido by early to mid April.
