AN EXAMINATION OF THE MAIN CHARACTERISTICS OF THE POLLEN SEASONS IN BUDAPEST, HUNGARY (1991-1996)

Aeropalynological methods are used to examine the flowering seasons of 18 different plant taxa in Budapest between 1991-1996. Start dates, e nd dates, length of flowering season and yearly totals of pollen grain s are computed and the main characteristics of the pollen seasons are examined in relation to meteorological factors. The aim is to obtain a picture of phenological characteristics of these taxa, the order of t heir flowering, the length of their seasons, the amount of pollen emit ted and the year-to-year variability in these parameters. By analysing phenological data in relation to meteorological data, conclusions can be drawn, which may be applicable in other cities, and which can help to create models for predicting phenological events in the future. Of the allergenic taxa, Ambrosia, Poaceae, Quercus, Betula, Fraxinus and Platanus emitted the largest amounts of pollen during the period exam ined. In general, pre-seasonal temperature had the greatest influence on the start of the season, where as higher temperature seems to promo te pollination. In the cases of woody plants, pre-seasonal precipitati on had no effect on pollen production. These results are in agreement with observations in areas with an atlantic climate. However the start of the grass season is influenced more by pre-seasonal precipitation, than temperature. The total yearly pollen count for the grasses also correlates with pre-seasonal precipitation. Thus, precipitation is an important limiting factor for the pollination of grasses, since the up per parts of the soil usually dry out during the spring.