Pollen seasons of selected tree and shrub taxa in Kraków and its neighbourhood

The aim of the study was to compare the dynamics of pollen seasons of selected tree and shrub taxa among measurement sites in Kraków and its neighbourhood. The study was performed in Kraków and Piotrkowice Małe in 2002, as well as in Kraków and Giebułtów in 2006. During the study the volumetric method was applied and pollen grains were counted along four horizontal lines. The lowest percentage of Corylus pollen and the highest percentage of Betula pollen were found in the analysed sites. The differences among start dates in various measurement sites in a given year were inconsiderable. Statistically signifi cant differences of SPI values for the majority of taxa were found between measurement sites and between seasons for Kraków. The pollen season dynamics showed one (Betula, Pinaceae) or more maximum values (Corylus, Populus, Fraxinus, Salix). The occurrence of many peaks could be explained by the appearance of several species within one genus in the studied area or by various weather conditions. In 2002 maximum pollen concentrations were recorded earlier than in 2006. The differences in these dates could be explained better by cumulative temperature >5℃ than >0℃