Changes in the pollen accumulation rate (PAR) of Cryptomeria japonica during the last 100 years were reconstructed based on pollen analysis of a sediment core from Lake Biwa dated by Pb-210 and Cs-137 methods. A comparison of the increases in the Lake Biwa PAR data with pollen data from afforested areas of C. japonica, planted during the 1950s, showed notable correlation. Before 1900, the PAR for C. japonica in the Lake Biwa sediment showed relatively low amounts of pollen, 900-1400 grains・cm^<-2>・year^<-1>. After 1900, the PAR increased slightly and, from 1920 to 1970, increased to between 2800-3700 grains・cm^<-2>・year^<-1>. From 1970 until the late 1970's the PAR increase continued, reaching 4200-4400 grains・cm^<-2>・year^<-1>, and further increasing by the early 1980's to 6300-7100 grains・cm^<-2>・year^<-1>. From the late 1980's and into the 1990's, the PAR showed a rapid increase from 8300 to 13400 grains・cm^<-2>・year^<-1>. Comparison of the results of the PAR data from Lake Biwa with estimated data for the mature afforested area of C. japonica suggests that recent increases of airborne pollen of C. japonica have, since the 1950's, been strongly influenced by cultivated forests of C. japonica. The PAR for the Lake Biwa sediment was also consistent with airborne pollen records of years with abundant C. japonica pollen dispersal. Notably, a comparison of the recent PAR data with a pollen analysis of sediment cores from Lake Biwa during the Quaternary period shows the quantities of C. japonica pollen during 3000-2000 cal yr BP, and during the second half of the last interglacial period, to be similar to those of PAR data after the early 1980's.

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A questionnaire survey of aerobiological networks worldwide was carried out by a committee coordinated by Prof. Jordina Belmonte in 2010. The results were reported during the 9th International Conference for Aerobiology held in Buenos Aires, Argentina in August 2010. Completed questionnaires were received from 465 sampling stations. Three categories of network reported back to the Committee: 1) Regional Networks (25), 2) National Networks (20), and 3) International Networks (3). The current report provides an introduction to the survey and to several important issues in aerobiology. The airborne pollen and spore samples were mainly collected using a Burkard type sampler, although Durham type samplers were used in a minority of cases. In the main the observations, and identification of the samples were carried out by university PhD students as part of their research studies and, to a lesser extent, by qualified doctors and teachers. The funding for these research projects was the main problem, and was often provided from the regional budgets of local governments; funding from state budgets was infrequent. There was also an example of private enterprise being able to provide some financial support for aerobiological survey work. In the main facilities for collection and observation of samples were shown to be universities and hospitals in cooperation with local government departments. The three International Networks provided internationally agreed documentation for observers, these included guidelines for sampling methods and sampling standards and, from an educational perspective, guides to pollen and spore identification using type specimens. Furthermore, to ensure a consistently high level of good data, regular quality control was recommended by the International Networks. Local public information services were, in general, provided with regular data on predicted levels of atmospheric pollen, as well as the actual levels of pollen. Pollen allergy risk was also disseminated by some of the more enlightened networks. Some networks, were also using an interactive internet system to answer questions from the general public.

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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.

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