Global Warming in Europe and Its Impacts on Floral Bud Phenology in Fruit Species

In the context of climate change, the fruit tree sector has specific vulnerabilities, such as perennial plantations and a complex flowering process to achieve fruit production. More particularly, warming impacts on floral bud phenology and their subjacent effects have been investigated for fruit tree species in different European regions. Numerous flowering data collected in contrasting temperature conditions (location, period) highlighted similar and significant advances in dates of different phenological stages for all the locations and fruit species. That means strong impacts of temperature changes in Europe (low interactions cultivar x temperature). The statistical analysis supports a general coincidence at the end of the 1980s between abrupt phenological changes toward flowering advances and marked climate changes toward higher temperatures. Moreover, the use of modelling parameters highly suggests that warming exerted two opposing effects simultaneously, i.e., a slower mean rate of completion for the chilling requirement and a higher mean rate of completion of the heat requirement. A more pronounced intensity of this last effect, in agreement with more marked temperature increases in winter than in autumn, might explain flowering advances. Nevertheless, some regional differences have been also highlighted, which needs further investigations.