Taxon-specific pollen deposition dynamics in a temperate forest zone, SE Poland: the impact of physiological rhythmicity and weather controls

High and low pollen deposition years in the period 1998–2010 were recorded for ten forest-forming trees in Roztocze (SE Poland) using Tauber-style traps. The coincidence of very high/low pollen deposition years recorded in Tauber traps and aerobiological data obtained by volumetric samplers shows that these phenomena occur simultaneously in different places across vast areas of a tree’s distribution range. The natural physiological rhythms displayed in abundance of flowering were considered on the basis of the observed data and published sources. The results obtained from applying Spearman’s correlation to pollen accumulation rates from Roztocze and the meteorological parameters confirmed several statistically significant correlations between temperature and summer precipitation prior to pollen emission and a negative correlation with the winter temperature before pollen emission. Air temperature, precipitation, growing season duration (its start and end), winter length and the number of winter days with a daily mean temperature below 0 °C were all considered. The best correlation coefficient results were obtained for the trees most abundant in the vegetation, namely Abies alba, Fagus sylvatica and Pinus sylvestris. Earlier findings on the controlling role of temperature and precipitation during the summer prior to pollen emission were confirmed, and a long period of winter dormancy was stressed as a factor favouring high pollen production. The examples from Roztocze reflected situations when a strong weather signal overrode the natural flowering rhythm. This was observable in the case of P. sylvestris, where pollen production reflected the air temperature of the previous summer or in the case of a mast year, which occurred across the whole distribution range of F. sylvatica in 2006.