Influence of meteorological conditions on male flower phenology of Cupressus sempervirens and correlation with pollen production in Florence

A description of the phenological development of the male flower of Cupressus sempervirens in Florence was performed on the basis of a one-year field monitoring of ten cypress populations in different climatic conditions; daily mean temperature was registered in each population and Cupressaceae pollen concentration in the atmosphere of Florence was monitored. Several methodologies were applied on the aerobiological data in order to identify the main pollen season (MPS) of Cupressaceae in Florence. The method that identified the MPS as 75% of the total annual pollen (MPS75) showed the best correlation with the phenological phase, which corresponded to the dispersal period of cypress. A clear relationship among male cypress phenology, daily mean temperature and Cupressaceae airborne pollen was shown. A phenological model able to simulate male cypress development was finally realized and validated on the basis of 6 years of aerobiological data. The model can predict the starting and ending date of the MPS75 of Cupressaceae in Florence and can be used fruitfully by the allergic population that can profit by the possibility of beginning an antiallergic therapy several days before the first symptoms and ending it when the pollen concentration in the air is low.