Pinus pollen season trend in South Spain

In Andalusia (southern Spain), Pinus species are found in mountainous areas and nature reserves, though some species are also grown as ornamentals in cities. Annual airborne pollen trends are regarded as an indicator of variations in climate prompted by overall climate change. Airborne pollen concentration also provides a useful tool for analyzing alterations in the distribution of vegetation in response to environmental factors and to changes in land use. The present study analyzed the Pinus pollen season over 22 years (1993-2014) in 4 Andalusian cities (Cordoba, Granada, Jaen, and Malaga), and examined correlations between airborne pollen concentrations and meteorological parameters (temperature and rainfall). Pinus pollen season lasted from March to June, starting first in Malaga and later in eastern Andalusia. Differences between the pollen curves for each city were attributable to differing proportions of pine species in each province. Temperatures during the months prior to flowering tended to fall, prompting delayed onset of the pollen season in most cities. No significant results were observed for rainfall patterns in most cities. Total pollen concentrations increased at most sites, suggesting that the recorded decline in pine-nut output was not influenced by flowering rates, but to the impact of a local pest.