Relationship between air temperature and the start of pollen emission in some arboreal taxa in Southwestern Spain

This work presents the first results obtained from the air of Seville relating the mean temperature of the months prior to pollination with the start of pollen emission in Alnus glutinosa, Ulmus, Moraceae, Platanus hispanica, Quercus, and Olea europaea. Pollen counts were made using a Burkard sampler which sampled the air of Seville between 1993 and 1997 (both inclusive). The start of pollen emission was taken as the day from January 1 on which the main pollination periods (1, 2.5, 5 and 10%) began. The data were related to the mean of the mean temperatures of the preceding months. The accumulated daily temperatures >0, 5 and 10°C from the beginning of the months prior to pollination and from the hypothetical end of dormancy were also calculated. While further years of observation will enable more reliable forecasting models, we have found some relationship between prior temperature and the start of pollen emission in these six pollen types. The best results so far are those for Alnus glutinosa, Ulmus, and Olea europaea.