The trend to earlier birch pollen seasons in the U.K.: A biotic response to changes in weather conditions?

Abstract

Records of the start of Birch pollen seasons monitored at three sites in the UK for periods of up to forty two years indicate a recent trend for the pollen seasons to begin earlier. This trend shows a close relationship to an increase in cumulative temperatures in the months of January, February and March recorded near each of the sites during the study period.