Is this an early spring?! The early hazelnut blooming is a proof of climate change!
Even though it is still the second half of January, observing hazelnuts in the Phenological Monitoring Area (PMA) planted by LIFE Clivut Team we have seen most of plants with blooming female flowers and almost mature male ones! This is a visible sign of climate change consequence.
Starting from 2007, we noticed that hazelnut female flowers were blooming in the half of February; as years went by, blooming gradually has moved to the beginning of the month. It means that this year blooming has started almost one month before normality!
The hazelnut is not the only plant to have had an early blooming: even Ranunculus lanuginosus has bloomed from more than one week, when it normally blooms in late spring!
How can we explain what is going on? Outside temperature affects plant physiology. In the last decades, climate change are meaning a gradual, but steady, temperature rising up, whose consequence are evident on plant development. Inside the city the increase of temperature is even more important because of heat island effect.
Hazelnut (Corylus avellana L.) is a bush species, which is really interesting for phenology studies because it has got male and female flowers separated on the same plant, but close on the same branch. Male flowers opens before female ones, they release pollen that arrives on female flowers thanks to wind (anemophilic dispersion). Fecundation of the female ovule occurs some weeks after the pollen arrive. Afterwards, hazelnut will be formed and mature in the month of September.
A different maturation period of female and male flowers is greatly important. In fact, when a too early blooming of female flower occurs it is dangerous for two main reasons. first of all, it can lead to fecundation failure; secondly, at early stage, a growing fruit can be damaged by late frost, endangering the harvest.
Phenology studies every stage of plant life cycle. Climate has an enormous influence on each phenophase: on leaf appearance, on blooming, even on fruit maturation. That is why phenology has an essential role in the analysis of climate change consequence in the ecosystems.
Each week LIFE Clivut Team observes the species inside the 3 PMA realised in the green areas of Perugia, one of the four partner city Project. Plant signs inside urban areas should not be underestimated. So, LIFE Clivut Team is working on a strategy for the mitigation of climate change effects creating an alliance with the green inside the cities.