An international team of researchers from Poland, France, the UK, the Netherlands and New Zealand, led by Prof Michal Bogdziewicz from the Faculty of Biology, decided to examine the relationship between weather and synchronous reproduction of beech trees across Europe. A publication on the issue was published today (8th of March) in the journal Nature Plants.
- "We were inspired by a recent study published in Science. Researchers from Switzerland found that the effect of temperature on leaf dieback varies depending on whether we consider the period before or after the summer solstice. The summer solstice is the longest day of the year, which always occurs on the same day, at the same time throughout the hemisphere," explains Dr Valentin Journé, a researcher working at Adam Mickiewicz University, Poznan, who led the analysis.
The researchers observed the detailed changes in the level of response of beech trees to temperature and found that trees across Europe suddenly started to 'read' the temperature on the 21st of June, just after the summer solstice.
- "The sudden response of beech trees is truly remarkable. As the day begins to shorten, after the summer solstice, beech trees across all corners of Europe open their 'window of sensitivity'. What is jaw-dropping is that the variation in day length during this time is genuinely small - we are talking about a few minutes over a week. However, the trees seem to be able to recognise this difference," says Dr Jakub Szymkowiak from the AMU.
The continental synchronisation of seed years is a result of weather synchronisation. However, it requires all plants to respond to weather variability simultaneously. Research by Prof Bogdziewicz's team has uncovered the existence of an astronomical clue which makes such precise synchronisation possible - it is the maximum relative day length at the summer solstice. It is precisely this hint that the European beech exploits, generating the ecological event with the greatest spatial synchronisation on the continent.
photo credit: Jakub Szymkowiak